Deleted important system files — how to solve?

[d_gomaiste]

Hey all —

So my brother deleted some files in /usr/lib, and now my iMac won't fully boot. No Time Machine backup unfortunately. Running 10.10.5.

I can still access my iMac's drive by booting into Target Disk Mode and viewing its contents with my Macbook. All of my files still seem to be intact, so I can save all important docs with no issue.

I've tried copying the contents of my Macbook's /usr/lib folder (also running 10.10.5) and I've tried copying the /usr/lib folder's contents from the Yosemite Installer (using Pacifist), but to no avail. I've also tried repairing disk permissions after copying, and still no luck.

It seems the best thing to do would be to simply re-install Yosemite, but when I boot into Recovery Mode, I am only given the option to install El Capitan. I cannot do this as several critical apps for my work do not support 10.11.

I've been looking into creating a bootable install drive, and it looks like I could simply do this with the Yosemite Installer and a USB key.

However, since Recovery Mode only allows for 10.11, the only other option I know of is booting into the Startup Manager to select the install drive. I'm a little worried, though — would doing this erase my data, or would it simply re-install OS X and keep all of my files intact?

Thanks!!

 

[T'hain Esh Kelch]

Recovery Mode works from Lion (10.7) and up, so just use that.

 

[d_gomaiste]

Recovery Mode works from Lion (10.7) and up, so just use that.

Thanks for the reply! Unfortunately, when I boot into Recovery Mode, I'm only given the option to install El Capitan, which I cannot install due to incompatibility with several apps I use.

Can I reinstall Yosemite from a bootable drive in Startup Manager without losing my data?

 

[T'hain Esh Kelch]

Ah, I misunderstod you.

But if you are running 10.10, then your recovery mode should also only install 10.10, not El Capitan. Also, isn't your first priority to save your files? Just reinstall the OS from the recovery drive, which doesn't delete any files. Use command-R, not Command-option-R.

 

[d_gomaiste]

Ah, I misunderstod you.

But if you are running 10.10, then your recovery mode should also only install 10.10, not El Capitan. Also, isn't your first priority to save your files? Just reinstall the OS from the recovery drive, which doesn't delete any files. Use command-R, not Command-option-R.

I also thought that would be the case, but it's only giving me the option to install 10.11.

Although saving my files is definitely a priority, I could really just copy my Desktop, Downloads, and Documents, as all of my other important files are on external drives. I'm mostly just trying to avoid having to reinstall EVERYTHING (I have a loooooooot of software installed).

 

[Erdbeertorte]

I've been looking into creating a bootable install drive, and it looks like I could simply do this with the Yosemite Installer and a USB key.

That should work. Just create a bootable USB drive with the Yosemite installer on it and install it over your damaged system.

The easiest way is using DiskMaker X for that:

http://diskmakerx.com

If your iMac was purchased new with Yosemite you can use Internet Recovery to install it again with holding cmd+option(alt)+R on startup.

 

[Fishrrman]

Just some thoughts.

First, to save your DATA files (as distinguished from "OS") -- use either CarbonCopyCloner or SuperDuper to clone your existing internal drive to an external backup. It may not be bootable (just as the internal drive is not bootable), BUT -- all your data files will be on that backup and available to you in "plain ol' finder format" -- just connect the backup and go. Set it aside for the moment.

Next, you need to create a standablone USB install drive of Yosemite. If you can't get Yosemite from Apple, then "do what you have to do" and get it from elsewhere, even "the torrents". Sometimes there is no other choice (I wish Apple would still allow users to download any version of the OS they needed, but....)

Next, connect your flashdrive installer to your Mac and boot from it.
Choose the reinstall the OS.
You may (or may not) need to use Disk Utiity to re-initialize the internal drive first.
This is why you took the time to create a CCC backup above -- if necessary, you can re-initialize the internal drive and reinstall easily from the backup.

Does the installer work?
Can you reboot to a "good boot" of 10.10?

If it was me, I would
a. backup
b. boot from USB-based installer
c. re-initialize internal
d. re-install brand new copy of OS
e. at the appropriate moment (using setup assistant), connect CCC backup and "re-migrate" all your accounts, apps, settings, and data

Yes, this is work, but should give you a fresh copy of the OS along with everything else "re-established" for you.

One last thought:
DO NOT grant to your brother administrative privileges on your Mac in the future, to avoid more such disasters!

 

[2ilent8cho]

Instead of CMD+R do CMD+ALT(OPTION)+R to enter recover, that should restore what the device shipped with not what is currently installed.

 

[Weaselboy]

But if you are running 10.10, then your recovery mode should also only install 10.10, not El Capitan.

Yeah... something is off here. If you are running Yosemite 10.10.5, a command-r boot to recovery will reinstall Yosemite.

OP> Has someone messed around copying different versions of the recovery partition perhaps?

 

[d_gomaiste]

That should work. Just create a bootable USB drive with the Yosemite installer on it and install it over your damaged system.

The easiest way is using DiskMaker X for that:

http://diskmakerx.com

If your iMac was purchased new with Yosemite you can use Internet Recovery to install it again with holding cmd+option(alt)+R on startup.

I'd heard about DiskMaker X, looks handy! Just to clarify — doing this would keep all of my data intact, correct?

Instead of CMD+R do CMD+ALT(OPTION)+R to enter recover, that should restore what the device shipped with not what is currently installed.

This DOES work, but my iMac was originally shipped with Mountain Lion — I'm not sure installing this would be a good idea.

Yeah... something is off here. If you are running Yosemite 10.10.5, a command-r boot to recovery will reinstall Yosemite.

OP> Has someone messed around copying different versions of the recovery partition perhaps?

Several months ago, I had upgraded to 10.11 and almost immediately reverted to Yosemite from an old back up, so I'm guessing that's what's causing the issue.

@Fishrrman, I appreciate the detailed response. I'm really trying to avoid migrating everything by hand, but if it comes down to it, I'll do it. My brother and I both use the iMac for work, so I can't revoke administrator privileges, but from what I can glean, it was really just an honest mistake on his part.

 

[2ilent8cho]

So long as Yosemite is on your purchased list on the App Store you can just format, install Mountain Lion then run the App Store and download Yosemite. Use your working Mac to confirm its in the purchased list when signed into the App Store.

 

[Weaselboy]

Several months ago, I had upgraded to 10.11 and almost immediately reverted to Yosemite from an old back up, so I'm guessing that's what's causing the issue.

Ah... yeah that is it. You probably just restored the Macintosh HD partition and not the recovery partition and that is whay you still have the El Capitan recovery partition on there.

Any OS X reinstall over top of the existing install will not erase your data.

 

[JohnDS]

Connect it to your other Mac using target disk mode. Then go to the Apps store, purchased items, download 10.10 to your working Mac and install it to the target disk.

 

[d_gomaiste]

Hey all —

Just reporting back to say that I got this worked out, and it was as simple as what @JohnDS recommended. Everything's in working order again, and I didn't even have to mess around with making a bootable drive or anything.

Thanks for all the help!

 

[basilt]

Recovery Mode works from Lion (10.7) and up, so just use that.

As i have a similar problem with sound etc. and my machine was bought used and dont have original osx, i was wondering
if the recovery mode deletes i.e. application file preferences etc. or what does it do exactly ?

Does the recovery mode installs AHT on my hdd, which is also missing ?

I need some apps to run for sure and not re-install them again until i format this hdd and give an end to my probs...

thanks

 

[TheBigDog]

Hey all —

So my brother deleted some files in /usr/lib, and now my iMac won't fully boot. No Time Machine backup unfortunately. Running 10.10.5.

I can still access my iMac's drive by booting into Target Disk Mode and viewing its contents with my Macbook. All of my files still seem to be intact, so I can save all important docs with no issue.

I've tried copying the contents of my Macbook's /usr/lib folder (also running 10.10.5) and I've tried copying the /usr/lib folder's contents from the Yosemite Installer (using Pacifist), but to no avail. I've also tried repairing disk permissions after copying, and still no luck.

It seems the best thing to do would be to simply re-install Yosemite, but when I boot into Recovery Mode, I am only given the option to install El Capitan. I cannot do this as several critical apps for my work do not support 10.11.

I've been looking into creating a bootable install drive, and it looks like I could simply do this with the Yosemite Installer and a USB key.

However, since Recovery Mode only allows for 10.11, the only other option I know of is booting into the Startup Manager to select the install drive. I'm a little worried, though — would doing this erase my data, or would it simply re-install OS X and keep all of my files intact?

Thanks!!

Re-install the OS

 

[Weaselboy]

As i have a similar problem with sound etc. and my machine was bought used and dont have original osx, i was wondering
if the recovery mode deletes i.e. application file preferences etc. or what does it do exactly ?

Does the recovery mode installs AHT on my hdd, which is also missing ?

I need some apps to run for sure and not re-install them again until i format this hdd and give an end to my probs...

thanks

If you just reinstall from recovery without erasing the disk first, it will just reinstall the system files and will not delete any of your applications or application settings or preferences.

It will not reinstall the AHT.

Since you bought this used, you may have an issue though. If the OS X version is above the one that came from the factory, then you run recovery to reinstall, you will be asked to enter the AppleID that was used to "purchase" the OS from the App Store... and you won't have that so will be stuck. If your Mac will run El Capitan for example, you can just go to the App Store now and purchase the free El Capitan update and that will then work when you update.

What year model Mac do you have and what OS X version are you on?

 

[basilt]

If you just reinstall from recovery without erasing the disk first, it will just reinstall the system files and will not delete any of your applications or application settings or preferences.

It will not reinstall the AHT.

Since you bought this used, you may have an issue though. If the OS X version is above the one that came from the factory, then you run recovery to reinstall, you will be asked to enter the AppleID that was used to "purchase" the OS from the App Store... and you won't have that so will be stuck. If your Mac will run El Capitan for example, you can just go to the App Store now and purchase the free El Capitan update and that will then work when you update.

What year model Mac do you have and what OS X version are you on?

thanks a lot for the very useful info you gave me, and could not find a solution insofar.
I have macpro 2006 1.1 with 2.1 upgrade, therefore 2.1, 8GB RAM, dual core 2x2.66 model. OSX 10.7.5 (11G63), NVIDIA GeForce 7300 GT 256 MB.

The osx came with locked accounts which i reset pwd. It has an admin account and a user one (Admin) which i login.

possibly this mac was on a network. I did not try to install new OSX yet, because i wanted to be sure first how to do it safely, and be able to upgrade via the hacks and add QC processors later on, and card to work with FCPX etc. After the old PPC install procedures, i am a bit confused on the mac recovery option, as i did not even know it existed !

I thought to burn a OSX lion 10.7.3 dmg on a flash drive with Diskmaker but not sure if i have to i.e. use a appstore version or retail etc. all these are unclear to me right now.

I also own an old PPC G5 DC 2ghz, to be sold soon, and i have a mac as a backup if i have to do something, although the OSX is leopard on G5.

Do you also know how to add the AHT on my macpro ? I downloaded the github version and not sure how to make the install of AHT valid on this system and allow me to boot at restart.

thanks for your reply mate !

 

[Weaselboy]

I thought to burn a OSX lion 10.7.3 dmg on a flash drive with Diskmaker but not sure if i have to i.e. use a appstore version or retail etc. all these are unclear to me right now.

Either version of Lion would work on that Mac Pro. Just boot to the installer USB and install without erasing anything.

 

[basilt]

Either version of Lion would work on that Mac Pro. Just boot to the installer USB and install without erasing anything.

i cross my fingers and will try the usb boot option and reinsall soon.