I ran into an issue that seems to come from Windows 10 Updates. Moments after logging in, I get a warning windows advising C:\WINDOWS\system32\config\systemprofile\Desktop is unavailable. There is no desktop, just a task bar and recycle bin.
The problems stems from the relocation of the default desktop from c:\users\default to C:\WINDOWS\system32\config\systemprofile\ but the Desktop folder doesn't get migrated. Thus, the error message.
I could not launch any program except task manager, so I worked out a convoluted procedure to launch a windows explorer instance and was able to show the now hidden Default user folder in c:\users, copy the contents and paste it in the new default user folder C:\WINDOWS\system32\config\systemprofile\default.
After following the procedure and rebooting. I was able to log in and was back to my normal desktop.
Here is the procedure I followed. It might be a bit overkill (copying all files in the default users folder but I only wanted to do it once. Sorry, no images this time.
On the task bar (if you see one) or press ALT+CTRL+DEL and select task manager.
In Task Manger, click File / Run New Task
Locate Desktop in the left panel
Right Click and select Properties
Click Find Target (wait a little bit for an explorer window to open)
On the top Menu click View
On the far right, click Options
Folder Options will open. Click View
Click the radio button Show hidden files, folders, and drives
Uncheck Hide empty drives
Uncheck Hide extensions for known folders and icons
Click Users in the address bar (This PC > Local Disk (C) > Users )
You should not see the Default user folder along with any other user folder as della s a Default.migrated
Double click on the Default folder to open the folder
On the menu ribbon (the menu below the top ment with File/Home?Share/View), far right, click Select All (or click white space in the details panel asn press CTRL+A). All files should be selected/highlighted
Right Click on any highlighted are and select Copy (or click Copy from the menu ribbon)
Navigate to C:\Windows\System32\Config - You may get a security box to allow you to access the folder. Click Continue
Click systemprofile - You may get a security box to allow you to access the folder. Click Continue
In the details white space, right click and select Paste (or click Paste from the menu ribbon)
Reboot - Press ALT+CTRL+DEl then click the power icon in the lower right and select Restart