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Time Machine thinks there is a new drive to back up

R

Ravich

macrumors 6502a
Original poster
Oct 20, 2009
773
0
Portland, OR
Cant figure out how to fix Time Machine.

I recently replaced an HDD (my home folder) by cloning it and then swapping them out. While there was no problem with the OS recognizing it as my boot drive, Time Machine doesnt recognize it as the same thing, so as far as it is concerned, there is an entirely new drive to backup, and there isnt enough space on my backup HDD.


How do I fix this? I have found the Time Machine options to be rather limiting.
 
Yup, there is. Delete the old backup and start over. Or delete most of the old backup, if you have some things you desperately need.
 
I have been staring at the time machine interface for the last 10 minutes and cant for the life of me figure out how to actually configure anything. How would I get time machine to delete the backup of the old drive and start a new one?
 
Ravich said:
I have been staring at the time machine interface for the last 10 minutes and cant for the life of me figure out how to actually configure anything. How would I get time machine to delete the backup of the old drive and start a new one?
Click to expand...

Just format the drive via Disk Utility and set it up through Time Machine again.

I experienced this problem, but the other way. Plugged my external into my Airport Extreme and Time Machine saw it as a new drive. I compiled various forum and blog posts but had to alter the sparse bundle and restore it onto the drive while it was plugged into the Airport. What a nightmare TM can be!
 
Ravich said:
I have been staring at the time machine interface for the last 10 minutes and cant for the life of me figure out how to actually configure anything. How would I get time machine to delete the backup of the old drive and start a new one?
Click to expand...

Are you sure it's doing an entire new backup? When I replaced the HDD in my wifes Macbook, it looked like it was doing a new backup. After a few minutes it did a somewhat small backup and was up to date. At first it said it had to replace 89GB, it appeared that it was just re-indexing the TM backup.
 
It must be since there isnt enough room for the backup all of a sudden, which shouldnt be the case since none of the drives have changed in size.


And I'm not formatting the drive because it has stuff on it that I want. There should be a way to configure time machine so that it discards the old backup and starts a new one, right?
 
Ravich said:
It must be since there isnt enough room for the backup all of a sudden, which shouldnt be the case since none of the drives have changed in size.


And I'm not formatting the drive because it has stuff on it that I want. There should be a way to configure time machine so that it discards the old backup and starts a new one, right?
Click to expand...

What are you trying to save? All of the info on your TM Backup should still be on your Mac right? If you format and make a new backup, it should be all the same info, unless you have something archived on it?

When you put the new drive in and formatted it, did you change the Volume name?
The default is "Macintosh HD" for your boot drive, but you said this was a separate disk for your "/home" folder. Maybe if the volume name is different from what your old(dead) drive was, TM gets confused?:confused:
 
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Time machine probably reads the drive's serial number to decide if it's the same.
 
If I had done that immediately it might have been a solution, but I didnt, and the drive has been modified since then, so I cant just revert to a backup.

I named it exactly the same thing, but Time Machine doesnt recognize it as the same drive, possibly for reasons such as the post above this one.
 
Assimilated said:
Why not just copy whatever it is you need from the drive, then reformat and start again?
Click to expand...

That's what I would do.:D
That's why my Time Machine drive is ONLY for Time Machine. Of course if you use it for other things and keep it organized, it wouldn't be a problem.
 
There HAS to be a way to reconfigure time machine so that it discards the old backup and starts a new one. I dont believe that Time Machine is that limited.
 
Still looking for a way to get this accomplished. Anyone know or should I call apple care and wade through lower end support?
 
Ravich said:
Still looking for a way to get this accomplished. Anyone know or should I call apple care and wade through lower end support?
Click to expand...

I haven't actually played around with all this since I don't want to mess up my settings, but in your (main) Library folder, there is a preferences folder and in it there is a time machine plist file. Don't look for this in the user's Library. Now, if you open up that plist file you will see the more advanced options for Time Machine. One of them is: RootVolumeUUID. There is a string there. I wonder what that is... There is also something called DestinationVolumeUUID. I bet the destination one is the Time Machine HDD and the RootVolume one is the HDD that is being backed upped. Now, you obviously would need to figure out what the UUID is to the HDD you now have installed is so that you can replace the RootVolumeUUID in that preference file. There is also a HostUUID, but I have no idea what that might be. How do you find your UUID? Open disk utility. Click on your drive. Not the manufacturer's name, but the name of your partition, the one with all the files. Mine for example is called JohnDoe HD (it isn't, it's my actual name but you get the idea). Click on file. Then get info. Then you will see something called: Universal Unique Identifier. Mines matches the string in my RootVolumeUUID in my Time Machine preferences. Maybe if you swap that information everything will work once again.

As stated before, I haven't played with any of this so tweak away at your own risk.
 
Last edited:
I'm sorry I can't be of more descriptive help, but these are the resources I used to maintain my previous backups, and still move my USB-connected hard drive from the USB port on my MacBook Pro to the USB port on my Airport Extreme:

 
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