So Time Machine is a pretty convenient way to backup your machine, and I use it to backup my laptop to an external FireWire drive. Although Time Machine backs up the "whole system," I assumed there had to be some exclusions, such as cache files or /dev, for example. After a short bit of digging, I discovered that these paths are specified in a standard property list at /System/Library/CoreServices/backupd.bundle/Contents/Resources/StdExclusions.plist

The full list is some 57 items, and is available below. Besides the expected cache items, the list includes some items I thought interesting:


Of these, the only one I find odd is the exclusion of logs. If your system goes haywire such that you restore it completely from a backup, it might be nice to see what went wrong.

[Update] Fixed the path to the StdExclusions.plist file.

Here's the full list of the excluded paths:

Contents Excluded

The contents of these paths are excluded, but the directories themselves are preserved as they are required for a successful restore.


Paths Excluded

These directories and their contents are excluded completely.

/Desktop DB
/Desktop DF
/Previous Systems
/Users/Shared/SC Info

User Paths Excluded

These directories and their contents are excluded per-user. The path is relative to the user's home folder.

Library/Application Support/MobileSync
Library/Application Support/SyncServices
Library/Mail/Envelope Index