Q: Time Machine only backing up Users folder

This only just started happening to me. I've been trying to troubleshoot it all morning. I noticed that only my user data was being backed up, but it only stopped backing up system files around August 30.

It was working fine in 10.8 (upgraded from 10.7.x) and for a week under 10.8.1, so I don't think it's related to 10.8.1.

I deleted all backups of the system drive from within Time Machine (which took a very, very long time to complete -- with no status indicators) and then added and removed the system drive from the exclusion list in an attempt to retrigger a backup, but it still is not backing up any system data.

I'm going to try completely resetting Time Machine.

Thanks. In that .plist, under ExcludeByPath, all of my system folders are listed. Weird. It's a mystery how they got added. I didn't add them, and they aren't in the exclusion list.

I'll check my other Mac later to see if that one changed as well.

My other Mac was fine, but comparing the com.apple.TimeMachine.plist files of the two machines reveals something interesting.

On the problematic Mac (Mac #1), before I deleted the .plist, all of the system paths (/Applications, /Library, etc.) somehow got added to ExcludeByPath on or around August 30. After deleting the .plist and starting fresh, the ExcludeByPath key and values are gone, as is expected.

But on Mac #2 (the Mac with no Time Machine problem), those exact same paths that were under ExcludeByPath on Mac #1 are specifically enumerated under IncludeByPath, whereas they are not specifically listed after starting fresh on Mac #1. (It's possible these existed on Mac #2 before my upgrade to 10.8.)

If the system paths were enumerated under IncludeByPath on Mac #1 prior to starting fresh, either the system, Time Machine, or another app changed IncludeByPath to ExcludeByPath. I cannot verify if IncludeByPath was in Mac #1's .plist because I no longer have the historical data.

In summary:

Mac #1 (Mac that stopped archiving system files):

• .plist contained system paths under ExcludeByPath
• after deleting .plist and resetting Time Machine, .plist no longer contains ExcludeByPath
• before and after resetting TM, IncludeByPath was/is absent

Mac #2 (Mac with no TM issue):

• system paths specifically listed under IncludeByPath

You have not gone mad!  I have the same problem.  See my posts of today in https://discussions.apple.com/thread/4557740

I had the same problem.

In my case, it was the com.apple.TimeMachine.plist file in /Library/Preferences, and not /Users/Me/Library/Preferences, that was causing the problem. Deleting it fixed the problem.

Yes, a known bug.  See #D10 in Time Machine - Troubleshooting.

We're trying to get as many reports to Apple as possible, so if you can, please do so and, if you don't mind, send me the Bug Report Number or Apple Care Case Number as noted in the blue box on the Running the diagnostics link there.

I reported an Apple case for this very issue back in July. I reset the Time Capsule and have done a couple of successful, full backup's since but i just checked my most recent back up and it's only the users folder.

I've got the case number so i'll do the diagnostic's steps and send you the details over later

Last time this happened i lost 3 months worth of data when i tried to do a restore!

I have a similar problem. When I try to restore anything, Time machine opens my user folder and apparently won't let me restore anything not in the my user sub-directories. I can't figure out how to access the Time Machine preferences to try to fix it. The only option I can find is by accessing Time Machine via my System Preferences and there is one option: exclude the external drive that has my Time Machine backup. Trying the OS X help menu, I can't find anything about Time machine preferences.

You might want to consider starting a new discussion. Since this one is a couple of years old, less people are likely to look at it. A new post would be much more visible. You can link to this one.

Start with A4 in the 1st linked article.

Time Machine Troubleshooting

Time Machine Troubleshooting Problems

Troubleshooting backup issues

A4 instructs me to go to the Time Machine preferences pane. If there is one, I can't find it. Also there's no Time Machine folder in my user-> libraries.

The Time Machine preferences pane is in System Preferences.

It isn't a Time Machine folder. Go to the Preferences folder and look for the Time Machine .plist.