osx mavericks update deleted all my files and apps from osx lion

I ran into the same thing. Here is what I had to do to get everything back.

1. I had to create a new dummy account.
2. While logged into the dummy account I found my old user home folder and renamed it something else.
3. I then created another user account named my original account name.
4. I proceeded to delete that account's home folder.
5. Then I renamed my old user home folder to the name of the newly created account
6. I logged into the newly made user account.
7. After that I went to the users folder and make my new account the owner of my home folder (it will still think your old account is the owner).
8. I applied the ownership to all enclosed items.
   • You should see all your desktop and documents return.
     You may have to log out and back in to have everything come back.

As for your apps. I found a Recovered Items folder in the root Macintosh HD directory. In this folder you should have an applications folder. You can drag your applications back into the Mavericks applications folder. Most of the applications should come over properly. I had to re-activate my MS office for mac. Everything else seemed to work fine.

My roommate just had the same problem with his MacBook Air. Apparently it had logged him into a new user account which it created.

Check in /Macintosh HD/users/ to see if your old account is still there, if that is what happened. It should appear as a locked folder with your username.

If this is the case, log out of this account, and log into your original account. All your files should now be in their correct places.

To delete the new account go to System Preferences > Users, unlock to make changes, select the account (make sure you have the correct one selected), and hit the minus (-) sign at the bottom of the list.

I believe what is being said is.... when you update to the new Operating System which isn't just an update...it's a full new Operating System, you automatically get a new Operating System User Account created. Then after the install, users are logging in to the new user account wondering where all their stuff is...including mail folders.

If you just log out of the operating system new user account and log back in with your usual user account and password, you should see ALL your stuff there as it was before. If so, THEN you can safely DELETE the new user account as it has nothing in it anyway (other than some recently downloaded emails likely).

Hope this helps. This may NOT be true for everyone reading this page but it was the problem for one user I new. She simply didn't even realize she was logged in to the Operating System as a different person or user account name.