I am facing the same issue with my fresh installation of windows 10 with the login screen flashing blue and lockscreen and the cursor showing busy circle. I'm pretty disappointed in myself for taking such a silly risk.Hi Kidneybot! I'm pretty disappointed in myself for taking such a silly risk.
Is there anything I can do about this, or am I screwed? It's just very rapidly flashing between a blue screen w/ a loading circle and my lock screen image. I've tried rebooting and it hasn't helped. Of course right after doing that I went to lock my PC to see if it worked, and as you can tell. So I took a risk and downloaded the 3rd party app here: and uploaded an image and hit apply. I set up my start menu and everything was working fine, but I wanted to change the image on the logon screen (or whatever you call the screen in between the lock screen and the screen where you enter your PIN/info). I upgraded from Windows 8 to 10 without a hitch an hour ago and kept all of my personal files and apps.
On the GitHub page for the program there was already a well-written tutorial on how to fix the issue.