The internet becomes far less helpful when people in forums just link to an answer somewhere else, only to have the link go dead in the interim between the lazy post and some future researcher. Ideally, answers should be copy/pasted with a link to the source. Would make things so much easier.
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Since Apple changed their link structure here on the Discussions site, the URL that baltwo posted was changed:
KirályApr 4, 2010 2:15 PM
Re: How to merge two user accounts?in response to ArisaemaDracontium
My favourite way to move files from Account A to Account B:
1) Log in to the A account.
2) Locate all the files you want to move. Move them to /Users/A/Public. Note: Don't move any System-created top-level folders, like Documents, Pictures, Music, Movies, etc. Just move their contents.
3) Log in to the B account.
4) Navigate with Finder to /Users/A/Public. Drag the files to the Desktop. This will make new copies of them that will have the correct permissions for User B.
5) Put the new copies of the files away in the appropriate places in B's home folder.
6) Delete the A user account if it is no longer needed.
Doing it this way will ensure that there are no permissions headaches with the files after they are moved.
Also, make sure that you BACK UP all of your data before starting.