I had trouble with my laptop after updating from 16.04 to 18.04 and re-installed the OS using "something else" so that my files would be preserved. This worked and everything runs fine but I cannot access my files. A terminal window search was able to locate all my files but I seem unable to access or move them. As far as I can tell there is only one user. Any ideas? P.S. I'm a real newbie.
If the files were left in place while you reinstalled the operating system, it's probably just an issue of permissions, in which case you should be to fix it with a simple:
sudo chown -R username:username /home/someuser
sudo chmod -R 770 /home/someuser
Obviously replace "username" with your username and "/home/someuser" with the path to your home directory, or to the location of the files in question.