Restored boot drive from Time Machine, data drive permissions are hosed I recently had a random and serious-seeming system failure, so chose to restore my boot drive (an SSD connected externally via thunderbolt).  Normally I back up with Time Machine locally, CrashPlan remotely, and I use CarbonCopyCloner weekly and store the images on an external drive not connected to my machine.

I thought this would be a cinch, since I had a clone from just a few days earlier.  However every restored clone exhibited the same issues, even when restoring from weeks before the issue began to appear.

So my fallback was to restore from Time Machine.  I nuked my boot drive and reinstalled Mavericks fresh, then restored from Time Machine.  Somehow that process removed my Recovery Partition so I installed Mavericks again on top of the restored drive, and everything appeared fine after that.  The previous issues all vanished.

Now the trouble is, Most of the directories on my separate "data drive" (the 1TB internal drive that came with my iMac) are set to "No Value" for the owner.  Of course I'm the admin on my system, so I can do a Get Info on every single one and change them, but then there are folders within folders within... you get the idea.  It's a total mess.

Now I can of course set the value of the top level folder to what I need it to be and apply to enclosed items, but that sets the user AND permissions of every single file and directory below, to the same thing.  This is merely a documents drive (symlinked from various user directories on the boot drive like Downloads, Documents, etc.) so I think it should be safe to do so, but I still really don't like the idea of giving every single file permissions of 755 along with the folders (or every folder set to 644 along with the files).

So, first is there any way I can get the permissions all back to what they were before and should be now?  Disk Utility won't do it since it's not a system volume.  And secondly, if there isn't a way to get the permission back to normal, is it safe to just make everything 755?  And by safe I don't mean in a security context (this is my personal machine at home, not worried about anyone accessing files they shouldn't), I just mean safe for the operation of OS X Mavericks.
You can change just the owner and leave the permissions alone. In fact, on the command line those are separate operations. If the problem is just ownership you can use something like:

sudo chown -R username /Volumes/blah/