Updated to 1903 but 'user'.000 now created and holds all my user files

This might not work for everyone, but I had this problem too, and was able to "fix" it.

I saw that the newly created second username folder only had a few files in it, belonging to Zune. Just as an experiment, I did 2 things:

Firstly, I rolled back windows, and then uninstalled Zune, and removed any old Zune file/folder I could get to (a lot of old Zune files are out of reach because Windows won't let you in those folders), and then restarted my computer freshly.

Secondly, I also unplugged my external hard drives, because someone from Windows had this mentioned in a list of actions I could do, and this was a simple thing to try, so that is why I did it.

Then I let Windows download and install the update (which was now called 1909 for some reason, in stead of 1903), and it worked. I had my normal username folder, and no .000 folder.

So I am not sure which was the exact fix. I remember though that it happened before that Windows 10 updates had problems when hard drives were plugged in, so this could very well be the issue again.

Thank you for this information, just went through this same issue after upgrading from Win7 to Win10 1909. After the upgrade my user was {User}.000, which was super annoying.

I noticed that I had 2 user folders after the upgrade:

C:\Users{User}

C:\Users{User}.000

The C:\Users{User}.000 folder contained ALL of my data but for some reason got renamed to .000

The C:\Users{User} folder (without the .000) was completely empty except for the following files:

C:\Users{User}\AppData\Local\Temp\WMZuneComm.etl.001 (.001 though .005)

The filename with "Zune" in it, let me stumble upon this post.

What I did to resolve the issue:

1. Uninstalled Windows 10 and rolled back to Windows 7 (you have a few days to do this after the upgrade). This is done by going to Settings > Update & Security > Recovery > Go back to Windows 7 (for me it was 7, could be 8 or 8.1 depending on what you upgraded from)
2. Once it downgraded back to Windows 7, I uninstalled the Zune software.
3. I then made sure to delete all of those nasty C:\Users{User}\AppData\Local\Temp\WMZuneComm.etl.001...005 files
4. Disconnected all of my USB drives (except the one I was using for the Win10 Upgrade)
5. Re-ran the Windows 10 upgrade
6. POW! no more .000 username this time after upgrading to Windows 10
7. I then reinstalled the Zune software (I had trouble finding the installer. Ended up doing a google search for and found a post on reddit with the installer. You can find the post by Googleing "site:reddit.com Zune Complete Package (270MB)")

Fixed!

Thank you for getting me started in the right direction, and hopefully this helps someone else in the future!

I do not have Zune, Xbox or anything else like that on my computers, so this is definitely not the cause of my problem. The upgrade created a new user (000) that windows 10 defaults to. I have created a work around because I mainly work with Word documents and Dropbox and that is where my troubles began. I reconfigured my privacy defaults in my original user Dropbox files and re-synced my files and now that is fine. But my concern is that windows is still creating files in (000) and my storage is getting full. I am afraid right now to delete everything in (000) for fear of losing important files in case my original user is deleted by another upgrade so I am going to give it a little time to see what happens. For a company that pretty much started it all you think their highly paid IT guys would be smart enough to figure a true fix for this very annoying bug! Thanks for the posts and Happy New Year Everyone:)

Damn! it's stunning that this issue still exists - my original post starting this thread was 6th July 2019, and this issue was present a long time prior to that. While many folks have been mentioning Zune as part of the cause, my issue was different since I didn't have Zune installed. What on earth is the problem here for MS?? For their own update (1903, etc) to break their own software (Outlook) shows exactly how much they give a damn.

Other than the Restore to Previous Version of Windows function, which can (maybe) roll you back to 1803, no easy fix that I've found.

I've just noticed 1909 and installed it on my daughter's computer (which did not have 1903, but she didn't have ZUNE either.  I think I installed that on my PC when years ago I had a Windows Phone!) and there were no problem.

I do wonder whether MS have actually sorted the problem out for the 1909 feature upgrade?  If so, well done MS.

Though it could just be that you had done what several, including myself, did, and removed the ZUNE bits and pieces?

My personal view is that the external HD is a red herring, and that it was ZUNE causing the problem for most of us.