This might be a bit more technical than what you're looking for but here's the deal with Time Machine backups:
Aside from regular UNIX file permissions (user/group/everyone each having their own read/write/execute permissions) Mac OS X also uses Access Control Lists (ACLs) that allow much more granular file/folder permissions settings.
Time Machine adds (prepends) the following ACL to all files:
group:everyone deny add_file,delete,add_subdirectory,delete_child,writeattr,writeextattr,chown
(The above ACL is folder-specific but maps to regular files like so: add_file = write, add_subdirectory = append, delete_child = <none>)
This means that all files/folders inside a Time Machine backup are locked for everyone (even the root user).
If you restore your files manually from a Time Machine Backup (i.e. if you do _not_ use the Migration Assistant) then all your files will keep those pesky Time Machine ACLs attached to them.
It is quite easy to remove the Time Machine ACLs. You have three options:
1) Swing the axe and remove the ACLs from your files/folders entirely (nothing wrong with that but not a very cautious strategy)
2) Remove the first entry from the ACLs of your files/folders (more cautious but not a perfect solution)
3) Remove specific restrictions from the ACLs of your files/folders (probably your best bet if you want to preserve non-Time Machine-imposed ACLs)
For all three options you need the Terminal which you will find in /Applications/Utilities
Option 1: Here's how you swing the axe:
If you know you have only your personal files in a folder called "My Recovered Files" on your Desktop and you know that those files don't have/need any fancy ACLs then you can type the following into your Terminal window:
chmod -R -N ~/Desktop/My\ Recovered\ Files
(if you don't know the Terminal-way of specifying a file/folder simply drag and drop the file/folder you want onto the Terminal window and the Terminal will type the correct file/folder name for you)
Option 2: Here's how you remove the first ACL entry
Same example as above. You have a folder called "My Recovered Files" on your Desktop. But in this case you have a few files with custom ACLs that you want to preserve. Type the following into the Terminal window:
chmod -R -a# 0 ~/Desktop/My\ Recovered\ Files
What makes the above solution "dangerous" is that it is not idempotent. An idempotent operation is an operation that can be applied over and over without changing the result after it has been applied once. Kind of like multiplying a number by 1. You can keep doing it but the result is always the same.
Why does that matter? Well, let's say that you have a file that already had an ACL before Time Machine prepended its own ACL entry. If you run the above command twice then you will have removed both the Time Machine ACL as well as the ACL that you probably didn't want to lose.
Plus the above solution is also not ideal for Time Machine files that are mixed in with other files. If any of these other (non-Time Machine) files have ACLs then the above command will remove those ACLs.
Option 3: Here's how you remove specific restrictions from an ACL
Aside from being able to specify which number entry of an ACL you want to remove you can also specify the specific restrictions you want to remove. So you could do this:
chmod -R -a "group:everyone deny add_file,delete,add_subdirectory,delete_child,writeattr,writeextattr,chown" ~
("~" means "my home directory", i.e. if your username is bob then "~" = "/Users/bob")
The above command is idempotent which means that you can run it over and over without ill effect. In fact, anybody can run it at any time. If there are no files/folders that have been locked by Time Machine in your home directory nothing will happen.
OK. I hope this was helpful for some people. I had the same problem with Time Machine permissions yesterday so I figured that I'd share what I found out.
By the way, if you want to view the UNIX permissions as well as the ACLs of a particular file/folder you can pop open the Terminal and type
ls -led /path/to/file_or_folder
(again, just drag and drop the file/folder you want onto the Terminal window if you don't know how to specify it the Terminal-way). If you want to learn more you can start by typing:
man ls
man chmod
into the Terminal window and you'll be on your way to becoming a geek. 🙂
(space bar to page forward, q to exit the man[ual] page)
