Delete Log and Other Unnecessary Files...

[GGJstudios]

You indicate that only most logs may not contain any "sensitive" or "private" information, so I have to conclude that some may, and the problem is I never know which ones exactly, so hence, the need to wipe them all regularly.

You then indicate that it's not a problem if you still control the computer. What exactly do you mean by that? Please elaborate how I can control my Mac to not write any "sensitive" or "private" information to any log files.

The only way anyone can read your log files is if they have access to your Mac, which means they could also read any other sensitive or personal data you have stored on it. In that event, log files would be the least of your worries. Log files do not store your passwords, financial data, etc. They are designed to log events that happen with an app or components of your OS, such as crashes, conditions, connections, etc. Before you blindly delete them, you should take some time to read a few log files to understand what kind of information is stored and what it's used for. You're taking action without understanding that action, which isn't wise.

 

[2012Tony2012]

The only way anyone can read your log files is if they have access to your Mac, which means they could also read any other sensitive or personal data you have stored on it. In that event, log files would be the least of your worries. Log files do not store your passwords, financial data, etc. They are designed to log events that happen with an app or components of your OS, such as crashes, conditions, connections, etc. Before you blindly delete them, you should take some time to read a few log files to understand what kind of information is stored and what it's used for. You're taking action without understanding that action, which isn't wise.

Can't some people or companies use apps that can read the files on my Mac without actually logging into my Mac? Isn't there a boot CD that gives that ability to read hard drives without actually logging in? If that is indeed possible, I don't think it's wise to get a false sense of security and leave all log files as they are, because even you have admitted that only most log files would not contain sensitive and private information, meaning that some indeed may.

 

[GGJstudios]

Can't some people or companies use apps that can read the files on my Mac without actually logging into my Mac?

No. No one can access your Mac unless you give them permission.

Isn't there a boot CD that gives that ability to read hard drives without actually logging in?

No. You should have control over what discs are inserted in your Mac.

If that is indeed possible, I don't think it's wise to get a false sense of security and leave all log files as they are, because even you have admitted that only most log files would not contain sensitive and private information, meaning that some indeed may.

Your concern about log files is based only on your ignorance of what they are and how they're used. As I suggested, read some log files and you'll see the type of data they contain. You're not being logical about log files and about protecting your Mac.

You don't need to worry about security of your data if you restrict who has access to your computer and if you practice safe computing.

Read the What security steps should I take? section of the Mac Virus/Malware FAQ for tips on practicing safe computing.

 

[2012Tony2012]

No. No one can access your Mac unless you give them permission.

No. You should have control over what discs are inserted in your Mac.

Your concern about log files is based only on your ignorance of what they are and how they're used. As I suggested, read some log files and you'll see the type of data they contain. You're not being logical about log files and about protecting your Mac.

You don't need to worry about security of your data if you restrict who has access to your computer and if you practice safe computing.

Read the What security steps should I take? section of the Mac Virus/Malware FAQ for tips on practicing safe computing.

If someone steals my Mac or I hand it in for service or someone else gets my iMac, there are boot CDs that allow reading the Mac hard drive. They can then access personal and sensitive information if any is stored in log files etc.

And my conclusions are only based on ignorance if your information that you have written to me is incomplete or in error, because it was YOU who said "most" log files will not contain any sensitive or personal information, indicating that "some" may.

And those links you posted, how can I know with complete certainity that they contain complete and accurate information? Perhaps the author is ignorant?

 

[GGJstudios]

If someone steals my Mac or I hand it in for service or someone else gets my iMac, there are boot CDs that allow reading the Mac hard drive. They can then access personal and sensitive information if any is stored in log files etc.

They can access any such information wherever it appears on your Mac, not just in log files. The data someone would be looking for would be in your user files, not your logs.

And my conclusions are only based on ignorance if your information that you have written to me is incomplete or in error, because it was YOU who said "most" log files will not contain any sensitive or personal information, indicating that "some" may.

I said "most" because I haven't read every log file on every Mac. I've never seen a log file contain any personal data. I've suggested a few times that you spend some time reading through some log files on your computer, so you know the type of data they contain, but you seem more inclined to argue rather than learn for yourself.

And those links you posted, how can I know with complete certainity that they contain complete and accurate information? Perhaps the author is ignorant?

It sounds like you're being deliberately argumentative and obtuse, rather than taking this opportunity to learn. As that appears to be the case, I don't care what you do with your Mac. Delete what you want, keep what you want. I don't care. I'm here to help those who want to be helped and share information with those who want to learn. As that doesn't appear to be your motive, you're on your own.

 

[2012Tony2012]

They can access any such information wherever it appears on your Mac, not just in log files. The data someone would be looking for would be in your user files, not your logs.

I said "most" because I haven't read every log file on every Mac. I've never seen a log file contain any personal data. I've suggested a few times that you spend some time reading through some log files on your computer, so you know the type of data they contain, but you seem more inclined to argue rather than learn for yourself.

It sounds like you're being deliberately argumentative and obtuse, rather than taking this opportunity to learn. As that appears to be the case, I don't care what you do with your Mac. Delete what you want, keep what you want. I don't care. I'm here to help those who want to be helped and share information with those who want to learn. As that doesn't appear to be your motive, you're on your own.

All my personal and sensitive data is stored in an encrypted file on my Mac, so they cannot read it even if they read my hard drive. But the encrypted file contain information that I know about and have placed there myself, but some sensitive and private information may be stored outside the encrypted container, it's this information I am concerned about and that I need to rely on programmers in the Mac community to write Apps to help me delete those place that information may be stored in.

As per your admission, you have never read every log file on Mac or from every App, so some Apps may store private information somewhere I don't know about, but that some cleaner Apps know about. For example, a few weeks ago I was the one that located hidden folders left behind by some Apps that other experienced Mac users did not know about when "completely removing Apps". So my point....even many experience users do not at times know every place information may be stored.

I find your last paragraph rather tantrum throwing, showing immaturity and lack of empathy. I have lost all respect for you as a result, as I had hoped you could be reasoned with maturely and I thought you had good empathic skills, my assumptions were in error.

Best wishes in your trying to educate people, but I believe you are spreading a false sense of security always telling people that the Mac can take care of itself, which I have found is completely untrue.

 

[GGJstudios]

As per your admission, you have never read every log file on Mac or from every App, so some Apps may store private information somewhere I don't know about, but that some cleaner Apps know about.

Not true, as none of the cleaner apps identify files to delete based on the presence or absence of personal information in the file contents.

I find your last paragraph rather tantrum throwing, showing immaturity and lack of empathy.

Hardly a "tantrum", but rather a realization that your unwillingness to check out the facts, but instead maintain an argument when you haven't done the appropriate research, implies you're not genuinely trying to understand and learn. It's also not immature to identify someone who appears to be more intent on making baseless arguments rather than dealing with facts.

Best wishes in your trying to educate people,

Thanks! It's been working well for years, as many are willing to learn.

I believe you are spreading a false sense of security always telling people that the Mac can take care of itself, which I have found is completely untrue.

It's not a false sense of security, regardless of what you choose to believe. It's fact. Your assumptions about what is or isn't true is suspect, as are the FUD-like arguments you make about log files, which indicate you haven't taken any time to learn what type of information is found in such files. If you were more aware, you wouldn't be eager to delete log files.

 

[snberk103]

I used to be a OS "under the hood tinkerer". Once I stopped, my Macs have never run better. I've been using OS X since early Tiger, and had to completely reinstall it - due to a "maintenance" application that was highly recommended. That's when I stopped, and that's when I noticed that OS X does a good job of handling, well, everything. It may not be as much fun... but I recommend that you just leave it alone.

Memory management is just fine, once you understand what OS X is doing. The one thing I do is quit everything just before I open up Photoshop if I want it to claim as much memory as possible (up to the limit I've set for it.) After it's opened up I'll reopen whatever I need.

I don't even know if this is still necessary... old habits....

 

[Mackilroy]

2012Tony2012: your computer's memory management is weird. I've never once needed a separate program to free up memory–OS X has always done an excellent job for me, and this on at least five separate computers. Nor have I ever deleted a log file (what's the point? Mine isn't even 40MB, which is a trivial amount of space on a modern drive). Your concern that there may be personally identifiable information in there is understandable, but I also think it's a bit silly. Were someone to want to ransack your files they would ignore the logs and go straight for your encrypted partition.

 

[2012Tony2012]

I will consider all comments and give it some thought. If I know that never any personal or private or sensitive information is stored anywhere on the Mac that I am not aware of, then I would stop using any "cleaning apps" all together and just let the Mac do it's thing. But until that time, I will continue to be diligent.

 

[brooksdbr]

Memory Management

2012Tony2012: your computer's memory management is weird. I've never once needed a separate program to free up memory–OS X has always done an excellent job for me, and this on at least five separate computers. Nor have I ever deleted a log file (what's the point? Mine isn't even 40MB, which is a trivial amount of space on a modern drive). Your concern that there may be personally identifiable information in there is understandable, but I also think it's a bit silly. Were someone to want to ransack your files they would ignore the logs and go straight for your encrypted partition.

I've had memory management issues over the last 6 months or so. Basically free memory down to 10Mb (the machine has 8GB) with 4GB in Inactive mode and lots of swap used. FreeMemory was mentioned on the previous page - I just log into Terminal and issue the purge command which frees up the Inactive Memory. Works perfectly.

 

[snberk103]

This is an important enough topic, that other people are going to read in the future. I think some clarifications are needed so that other people don't make the same mistakes that I think you are making. So.... go ahead and do what you think is best. It is your computer after all.

...., but some sensitive and private information may be stored outside the encrypted container, it's this information I am concerned about and that I need to rely on programmers in the Mac community to write Apps to help me delete those place that information may be stored in.

As per your admission, you have never read every log file on Mac or from every App, so some Apps may store private information somewhere I don't know about,....

1) Every year there is a big hacking contest held in Vancouver. Since it is local, and since it involves Macs, I read the results carefully. Not once has it been reported that a Mac was compromised due to information found in the log files. And those people do in fact read every single line found anywhere on a Mac.
2) OS X is based on BSD/UNIX. It was designed from the ground up to be secure. Leaving sensitive info in log files is a rookie mistake. So, while individual apps may make that mistake, the OS won't be. This thread has been about deleting System Logs, not individual app's logs.

While GGJstudios may not have personally read every single log on every single, I believe he is correct because his conclusions are backed up by people who do in fact know about these things. In the same way that I haven't read every single study on the theory of gravity, and yet I believe that when I drop something it will fall down.

One other thing... you mention that you are relying on programmers in Mac community to write the apps to delete these logs that allegedly hold sensitive information. But, if these programmers have less than pure motives, then they may be using fear to get you to use a cleaning application that compromises your security. In a case like this, I would trust Apple's programming more than a small 3rd party outfit that may be using your fear of being compromised against you.

Best wishes in your trying to educate people, but I believe you are spreading a false sense of security always telling people that the Mac can take care of itself, which I have found is completely untrue.

[/QUOTE]Actually, you have only heard other people's opinions about it. You have not really posted any evidence. The evidence is actually the other way 'round. I have never read any reports from people in the business that indicates that sensitive information is being held in log files.

I will consider all comments and give it some thought. If I know that never any personal or private or sensitive information is stored anywhere on the Mac that I am not aware of, then I would stop using any "cleaning apps" all together and just let the Mac do it's thing. But until that time, I will continue to be diligent.

As I said before, you had also better be sure that those cleaning apps are not compromising your system. There is a much higher probability that someone will write a piece of malware and get you to install it by feeding on your fears. The chances of someone getting physical access to your system is low, and then finding that nugget of information that was written in error to a log file - a nugget that professionals are constantly looking for and apparently not finding - is very very low.

So... do what you want... it's your computer. But please do not recommend it as a good course of action. If it makes you feel better, then great. But your advice is making other people less secure, not more secure. imho, of course....

 

[2012Tony2012]

This is an important enough topic, that other people are going to read in the future. I think some clarifications are needed so that other people don't make the same mistakes that I think you are making. So.... go ahead and do what you think is best. It is your computer after all.


1) Every year there is a big hacking contest held in Vancouver. Since it is local, and since it involves Macs, I read the results carefully. Not once has it been reported that a Mac was compromised due to information found in the log files. And those people do in fact read every single line found anywhere on a Mac.
2) OS X is based on BSD/UNIX. It was designed from the ground up to be secure. Leaving sensitive info in log files is a rookie mistake. So, while individual apps may make that mistake, the OS won't be. This thread has been about deleting System Logs, not individual app's logs.

While GGJstudios may not have personally read every single log on every single, I believe he is correct because his conclusions are backed up by people who do in fact know about these things. In the same way that I haven't read every single study on the theory of gravity, and yet I believe that when I drop something it will fall down.

One other thing... you mention that you are relying on programmers in Mac community to write the apps to delete these logs that allegedly hold sensitive information. But, if these programmers have less than pure motives, then they may be using fear to get you to use a cleaning application that compromises your security. In a case like this, I would trust Apple's programming more than a small 3rd party outfit that may be using your fear of being compromised against you.

Actually, you have only heard other people's opinions about it. You have not really posted any evidence. The evidence is actually the other way 'round. I have never read any reports from people in the business that indicates that sensitive information is being held in log files.

As I said before, you had also better be sure that those cleaning apps are not compromising your system. There is a much higher probability that someone will write a piece of malware and get you to install it by feeding on your fears. The chances of someone getting physical access to your system is low, and then finding that nugget of information that was written in error to a log file - a nugget that professionals are constantly looking for and apparently not finding - is very very low.

So... do what you want... it's your computer. But please do not recommend it as a good course of action. If it makes you feel better, then great. But your advice is making other people less secure, not more secure. imho, of course....

1. Can you provide a source which shows that they read every single line in ALL log files for ALL apps that exist on the Mac?

2. Can you prove and show that NO system file logs contain any information about internet activity?

3. Just because you believe in gravity, does that make you 100% certain that no private or senitive information is saved and stored on your Mac?

4. Do you have evidence that Apps such as Ccleaner, IceClean, Magician, Onyx, iBoostUp have bad motives and that their apps are part of some conscipracy?

5. Your whole post seems based on what you have heard from other people's opinions about Mac being secure. You have not really posted any evidence. Have you personally read every single line in every single log file to accuarely conclude that there is no private or sensitive data anywhere on your Mac stored somewhere without your knowledge? OR are you making assumptions?

 

[snberk103]

....
5. Your whole post seems based on what you have heard from other people's opinions about Mac being secure. You have not really posted any evidence. Have you personally read every single line in every single log file to accuarely conclude that there is no private or sensitive data anywhere on your Mac stored somewhere without your knowledge? OR are you making assumptions?

OK, you're right. There is a possibility that there is something that might be sensitive that can occasionally be written for a short period of time to a log file. Lots of things in life are 'possible'.

But I'm not going to lose any sleep over it. Just like I'm not going to lose any sleep about Feb 15th. Even though I only read expert opinions that we will be fine, I have not actually done the orbital calculations myself.

 

[GGJstudios]

Have you personally read every single line in every single log file to accuarely conclude that there is no private or sensitive data anywhere on your Mac stored somewhere without your knowledge?

No app that you could install will scan every single log file, looking for such information, either. Deleting log files is ridiculous, as they will only be recreated by apps as you run them, and in the interim you've lost potentially valuable troubleshooting information. The purpose of log files is not to store personal or sensitive information, but to assist in tracking app execution events. No reputable app stores any personal information in log files.

 

[dyn]

You don't need to clean out logs, as they don't take much space and you will need them for troubleshooting purposes. You're not helping your Mac by deleting such files.

Logs are not a requirement for troubleshooting at all. They can be a very handy tool to pinpoint a problem/cause but it can also be very confusing (too much information). That's why there are systems like syslogd and the maintenance scripts. They only keep logs up to a certain part. Keeping nearly everything is absolutely useless.
How much of the logs will be kept is something that the sysadmin usually decides. It seems that in this case someone wants to limit the amount of logs to safe some disk space. I don't think it will do much harm. Most problems are instant and repeatable anyway so it is very easy to recreate errors messages in the logs.

Saying that he is not helping his Mac by doing this shows a misunderstanding of what a logging system is supposed to do. One should be asking himself what he gains by limiting the logging. In this case it's probably lot's of effort for something that brings you little gain in reducing disk space and amount of writes to the ssd making it pointless. The only thing you'll benefit from this entire process is gaining knowledge of various systems in UNIX (OS X in particular). The way OS X is doing the logging and clean up of old logs is fine. The defaults are good enough for the average person.

Can't some people or companies use apps that can read the files on my Mac without actually logging into my Mac? Isn't there a boot CD that gives that ability to read hard drives without actually logging in?

Yes there are, many. They all require physical access to your machine. Usually in security this means that all hope is lost anyway because they have full access to the machine which is why some people don't bother using encryption like encrypted disk images (standard in OS X, TrueCrypt, etc.) or whole disk encryption (PGP, Filevault 2, etc.). If you use encryption then of course they can't just read data, that's the whole point of encrypting something To prevent somebody from booting into some kind of cd to get to the data on your disk you need to do at least 3 things:

1. set up a firmware password with a strong password to prevent them from booting into anything other than your OS X install (this causes problems with things like single user mode, target disk mode, etc. for these to work you need to temporarily disable the firmware password)
2. set up Filevault 2 or PGP in order to encrypt the entire disk (data will be unreadable when not unlocked; you do this by logging in as a user that is allowed to unlock it)
3. change the read/write/execute permissions on your homedir so only the owner is able to read/write/execute to prevent other users on that same system to be able to see/read/execute files in your homedir

If you really want to be secure you need to power off the machine instead of using the hibernate/standby/sleep modes. This will clear the RAM which will disable the possibility to capture the encryption password (when using whole disk encryption with something like Filevault 2) via something like DMA (through Thunderbolt for example).

Security means that you need to apply it to several levels. There simply is no such thing as applying only 1 measure to be safe. Think of security as a plan, a design. Deleting logs or certain information in those logs is completely useless in this case. The actual data (docs, pictures, etc.) is much more interesting. You can't commit fraud, identity theft, etc. with information from most log files but you can with things like a picture from someone's passport, creditcard, etc.

 

[GGJstudios]

Logs are not a requirement for troubleshooting at all.

I never indicated they are a requirement. They can be helpful, if they're not deleted.

Saying that he is not helping his Mac by doing this shows a misunderstanding of what a logging system is supposed to do.

No, there's no misunderstanding. Aside from saving a relatively small amount of space, there is zero benefit in deleting log files, which means you're not helping your Mac by deleting them.

 

[dyn]

I never indicated they are a requirement. They can be helpful, if they're not deleted.

I never said you did. Changing the default settings for logging and running the maintenance scripts does not delete all the log files. It rotates them and deletes old logs. When it does the rotation and deletion is something that one can change if one wants to.

No, there's no misunderstanding. Aside from saving a relatively small amount of space, there is zero benefit in deleting log files, which means you're not helping your Mac by deleting them.

A Mac does not benefit from changing the logging nor from leaving it at its defaults settings. It's the user who does. You change the logging settings for your own benefit. The Mac is just a machine. It really doesn't care if it logs like there is no tomorrow or not at all. You log certain things for a certain period for a specific reason. Troubleshooting is only one of the reasons why you log. Security audits, checking if something actually ran, create stats/reports, etc. are all reasons why one would want to log. So yes, there definitely is a misunderstanding from your part. If you are not tech savvy then those logs are meaningless to you and you could disable them completely (knowing that when left enabled it might help others in helping you, could prevent a complete reinstall of the machine!).

 

[colourfastt]

This thread has won the "tinfoil hat" award!

 

[2012Tony2012]

OK, you're right. There is a possibility that there is something that might be sensitive that can occasionally be written for a short period of time to a log file. Lots of things in life are 'possible'.

But I'm not going to lose any sleep over it. Just like I'm not going to lose any sleep about Feb 15th. Even though I only read expert opinions that we will be fine, I have not actually done the orbital calculations myself.

Don't believe everything you read

Also, can you point me to some experts sources where they mention going through every single line on Mac OS logs and where they concluded no sensitive or private data is never written there?

----------

No app that you could install will scan every single log file, looking for such information, either. Deleting log files is ridiculous, as they will only be recreated by apps as you run them, and in the interim you've lost potentially valuable troubleshooting information. The purpose of log files is not to store personal or sensitive information, but to assist in tracking app execution events. No reputable app stores any personal information in log files.

You may be right, however I cannot be 100% certain that you are.

----------

I never indicated they are a requirement. They can be helpful, if they're not deleted.

No, there's no misunderstanding. Aside from saving a relatively small amount of space, there is zero benefit in deleting log files, which means you're not helping your Mac by deleting them.

Can you give a few different examples where you personally looked through your log files, and for what reason and how it helped you?

 

[GGJstudios]

A Mac does not benefit from changing the logging nor from leaving it at its defaults settings.

Changing logging settings is not what's being discussed here. What's being discussed is using 3rd party apps to blindly delete logs, without regard for their content or use, which provides no benefit apart from the small amount of space that is temporarily gained, with the associated disadvantage that such information may be needed in the future. In addition, the reasoning behind the desire to delete logs being expressed here is not space savings, but an unfounded fear that such logs contain personal, private, sensitive information, which they do not.

Security audits, checking if something actually ran, create stats/reports, etc. are all reasons why one would want to log. So yes, there definitely is a misunderstanding from your part.

The fact that I refer to only one use for such logs as a reason not to delete them does not in any way suggest that I don't understand other uses for them. As it is far more likely that the average user would want to refer to logs for troubleshooting purposes than for security audits or reporting or other uses, it's more appropriate to discuss a purpose for them that is more likely to be used. You have absolutely no idea what I do and don't understand about logging and the content of logs, so kindly refrain from making baseless and false claims about my understanding.

If you are not tech savvy then those logs are meaningless to you and you could disable them completely (knowing that when left enabled it might help others in helping you, could prevent a complete reinstall of the machine!).

This is one example of why I recommend against deleting them blindly, especially for the reasons being suggested.

 

[MacTech68]

Sheesh.

I will say, that there are a few issues NOT discussed here.

1. Early versions of MacOS X rotates logs and purges old logs early in the morning (around 3:15am). If your machine is never running at that time, log files can become quite large, though insignificant when compared to current hard drive sizes. Later versions attempt to get around this problem by delaying the scheduled time by the amount of time your machine was asleep or shut-down, but again, if your machine is not running at that NEW scheduled time, the maintenance scripts may not run.

2. The maintenance scripts in themselves do not rotate and purge all log files, so there may be log files that are never rotated or purged.

3. Where log files can become significantly large, you may notice a lag in performance or non-functioning add-ons. This can especially occur after a system update, after installing new software, or migrating a system from one Mac to another. If this happens, then getting to the root cause is pretty important, but easily reproducible even if the log files are deleted.

4. Deleting log files in itself, does no harm to your system. Even the system eventually deletes logs after a pre-determined period of time. If you like doing it, or it gives you a feeling of security, go ahead and do it, but there is no evidence that it actually makes your machine more secure - but of course, that could change. If there was indeed any app that put clear-text passwords or other identifiable information into log files, they most likely would be discovered at least within 6 months by the community at large. For example, there was an instance where VM Swap files were retaining passwords which was discovered by the Mac community, though that has long since been resolved.

That's my 2c. I await to be flamed.

 

[2012Tony2012]

ATTENTION: GGJstudios

Can you give a few different examples where you personally looked through your log files, and for what reason and how it helped you?

 

[GGJstudios]

ATTENTION: GGJstudios

Can you give a few different examples where you personally looked through your log files, and for what reason and how it helped you?

I don't recall specifics at the moment, but I've used them several times over the years to help diagnose problems with apps and track other activity. There have been several threads posted where logs were used to identify and understand system and app behavior.

 

[snberk103]

Don't believe everything you read

Also, can you point me to some experts sources where they mention going through every single line on Mac OS logs and where they concluded no sensitive or private data is never written there?
...

By the same token can you point me to some expert sources that says that the 3rd party apps you are installing to delete the logs (and potentially giving Admin privileges to) are not themselves copying the info and sending it out?

I would rather believe that the absence of any evidence that log files - installed on every Mac and readable by anyone - contain sensitive information means that they don't have sensitive info. As opposed to the closed and proprietary nature of 3rd party apps that are installed in a minority of Macs, and whose results are not transparent to everyone.

But it's your call.... it is your info after all.... trust the 3rd party apps developers who can disappear overnight.