Here's the context: I have about 400 students with Time Machine backups from Lion computers. We wiped and re-imaged their laptops with new software AND with Mountain Lion. We just discovered that you can no longer use Time Machine to "Browse other Backup Disks" in Mountain Lion. (The option is there, but the functionality is broken.) The students will have to navigate in Finder to their most recent backup and manually drag the files to their new computer. However, the Library is hidden on the disk, and they can't access it without unhiding it. I know how to unhide the folder using this method in Terminal:

cd ../../Volumes/WhateverTheyNamedTheirBackupDrive/Backups.backupdb/Student's MacBook Air/2012-07-30-192502/Macintosh HD/Users/StudentsUserName ls chflags nohidden Library

Does anyone have any idea how I could script something that unhides the mounted backup folders' libraries? I'm struggling with the extreme variability of student backup disk names and folder names within a Time Machine backup. (And I can't exactly expect 400 kids to get it right in terminal.)

  • If you can author a script that works, would you trust them to run it? This is probably the simplest route if so.
    – ephsmith
    Commented Aug 19, 2012 at 23:29
  • Hi Beth! Can we assume the short names off he students is the same on the backup drives as the current machine? Also - is your plan to wipe the backups or have the new machines inherit the old files? (please say yes to the second question)
    – bmike
    Commented Sep 19, 2012 at 0:18
  • It sounds like specific files need to be copied over, but you can't due to the variability of backup folder names. What about a script that copied the right files once the kids manually identified the proper backup? Or are the required files individual to each kid?
    – robmathers
    Commented Sep 19, 2012 at 2:01

1 Answer 1


Could you use something like this?

sudo /System/Library/Extensions/TMSafetyNet.kext/Helpers/bypass chflags nohidden /Volumes/*/Backups.backupdb/*/*/*/Users/*/Library/

bypass was in /System/Library/Extensions/TMSafetyNet.kext/Contents/MacOS/bypass on Lion.

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