2011-11-06 iTunes iPad Backup

The media on this iPad cannot be backed up because there is not enough free space on this computer to hold all of the backed up files (31.30 GB required, 3.57 GB available). Would you like to continue to update this iPad? Continuing will result in the loss of all media on this iPad.

I hate you! My external disk drive has 214.03 GB available. Now what?

I think what I’ll try is move all my existing backups from ~/Library/Application Support/MobileSync/Backup/ to my external drive and link the new location to the old location.

  1. it did not work – even though this is what other people suggest as well
  2. tried it with a symbolic link instead of the links Finder creates, but it didn’t work, either
  3. tried moving MobilSync to the external disk and symbolic linking it, but it didn’t work, either

iTunes keeps telling me that there’s not enough space. >{

Hours later... I’ve deleted ~/Library/Caches/* and ~/Downloads/* for both accounts on this machine and I have emptied the Trash many times... and finally—finally!—there is enough free space to start the upgrade including a media backup.

Curious, however, I wanted to know where stupid iTunes is saving the backup to. Well, theoretically lsof will “list open files”. Let’s see:

Pyrobombus:~ alex$ lsof|grep -i backup 
AppleMobi 895 alex  txt      REG       14,2    499200 11536761 /System/Library/PrivateFrameworks/MobileDevice.framework/Versions/A/AppleMobileDeviceHelper.app/Contents/Resources/AppleMobileBackup
AppleMobi 895 alex    7w     REG       14,5   2097152  3720396 /Volumes/Extern/MobileSync/Backup/346b7073bd3e141e94284c421ed96dc724f88ff9/Snapshot/8277946022662205f468e8e329528bfa8b0c9fbf.upload

I noticed that you might have to call this repeatedly because at particular points in time the process might not be writing backup files.

Anyway. What does this tell me? iTunes checks the available disk space on the default drive where it thinks the backup will be created, even though I moved the directory to an external disk. 👎

Well, I was hoping this fixed the stupid problem, but not so:

An error occurred while backing up this iPad (-50). Would you like to continue to update this iPad? Continuing will result in the loss of all contents on this iPad.

Now what? Retry? I wonder what that means, exactly: Loss of all in-app purchases? What if the app is no longer supported—are the in-app purchases that I am unable to download lost forever?

Another question poses itself: Do I need a backup as part of this upgrade process? When I sync the iPad before doing the upgrade, I see that it is doing a backup. When I check iTunes Preferences → Advanced → Devices → I see “Alex Schröder’s iPad – Today 11:20” (not quite what I expected but close enough). Perhaps I can just upgrade the iPad and then restore this backup?

Googling for this error leads me to a thread where a user is saying “I had my MobileSync folder symlinked…” This is exactly what I did to avoid the first error. Needless to say, this makes me very unhappy.

What I’ll try next is deleting the symlink without moving the backup data back to the main drive and upgrade. We’ll see about the various backups after the upgrade. Perhaps the 31.30 GB required are just a temporary thing. I sure hope so.

It worked! When I came back this morning I saw Syncing Photos to “Alex Schröder’s iPad (Step 66)—Copying photo 16600 of 19540”




I love Apple - until it doesn’t work...

Jovial Priest 2011-11-06 20:33 UTC

My thoughts exactly! sigh I switched to Apple after having used various GNU/Linux distributions for years. I spent a lot of time tinkering with the system. Apple appeared to offer a fix to this problem, and it just works—most of the time. When it doesn’t work, though...

AlexSchroeder 2011-11-06 23:04 UTC

Sorry to hear you’re in iPad hell. I just brought on line a 2 TB external (2 TB ... and I recall the days of tape) for my media. In my case, it was the prior drive going down, taking all the music with it (and nearly the MacBook, whose hd was also entirely full). Managed to recover an old episode of the podcast, plus (thanks to iCloud, I’ll admit) a ton of music.

Brian Isikoff 2011-11-07 15:28 UTC

Episode 60 was good! The amount of work producing a sound track for every player is staggering, however. Wow!!

AlexSchroeder 2011-11-12 09:16 UTC

Well, many years later, I got the same error message. I followed these instructions from the Internet and it worked:

mv ~/Library/Application\ Support/MobileSync/Backup ~/Library/Application\ Support/MobileSync/old_backup
ln -s /Volumes/Data/MobileSync/Backup ~/Library/Application\ Support/MobileSync/

I already had a /Volumes/Data/MobileSync/Backup so this setup must have worked previously. I’m not sure when the Symlink got replaced with a real directory. My guess is that at one point I must have started a backup without my Data Volume being mounted. My guess is that iTunes decided to delete the dangling symlink and start again, silently duplicating all the data on my primary disk.

I guess I should do this for Claudia’s account as well.

– Alex 2017-11-06 22:03 UTC

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