There is a warning when you rename the user folder. The computer asks you for your password if you are about to do anything dangerous.

This is indeed a feature. If you reflexively type in your password whenever the computer asks for it, then this will bite you. Once you type in your password, the computer will do whatever dangerous thing you just asked it to do.

This will usually bite power users who are switchers from Windows.

Guidelines for Power users and Switchers:
- If you did not create the file/folder then don't move/rename/delete it.
- If the computer asks you for your password, stop and think. You are giving the program asking for the password, permission to do *anything*.

Unfortunately, there isn't always a warning. I don't recommend testing it ;-) but it's possible to change your home folder's name without seeing an authentication dialog.

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Dan Frakes / Senior Editor, Macworld / Senior Reviews Editor, Playlist

There has been a warning up to 10.2.x, but sometime then it was gone. I just discovered that I cannot rename my home-folder, which is FileVault protected, at all.

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this is not the sig you`re looking for.