Curious File extension

Question

On selecting hidden files and folders, I noticed ntuser.dat.regan613 - I understand that ntuser is a legitimate file but regan613?..A google search has rendered nothing of interest and I am the only user of my computer so it cannot be another account. Any assistance appreciated.

Answer 1

Files can have any extension and its contents aren't affected. A jpeg can have a .txt extension and still be an image file. Sometimes when files are backed up by programs they simply add a string to the end of the file name. So settings.reg becomes settings.reg.backup when they are edited.

ntuser.dat are unique settings you have selected for your windows user. Every time you create a new user or change the user name one of these files are created. This file remains for the old account. You can delete the accounts that you no longer use but make sure you only delete the one not in use or needed.

Answer 2

the ntuser.* files form the Windows Registry "database". If you are seeing a lot of ntuser files in the current users home folder, you are reasonably safe to delete all but the latest of each type (.dat, .log, etc). If you are seeing ntuser files in other users home folders, probably best to leave those until you log in as that user since Windows will be protecting the live files.

Not certain exactly what created the files you've found I'm afraid though I suspect they may have been created by some tool you used previously to tidy up your PC.

You can use the following command from the command prompt to list the ntuser files for the logged in user along with the owning entity:

dir /a:HS /Q %HOME%\ntuser*

You will see that most are owned by NT AUTHORITY\SYSTEM, one may be owned by BUILTIN\Administrators so you will need admin privileges in order to delete any of them.

If you aren't sure but want to tidy up, move them to some other folder and reboot then keep the moved files for a while.