Sudden switch from Local User to MS account - can not switch back

Try logging in here, and see if your computer is listed in your devices
https://account.microsoft.com/devices/content

lrw, I'm sorry but I will be unavailable for several hours now. Were you able to login to your MS account in a browser?

lrw said:

Yes, of course. MS live website is outlook.live.com. Sorry for the confusion. Anyhow, I used command prompt to delete the old account and now only have my new local account as a choice for Windows login which is good.

Okay sorry - I misunderstood about what/where you were logging in.
Only 1 local user account now - good.

lrw said:

Trying to rename the old /Users/oldLocalAccount but it seems to still be in use. Even after a reboot.

The only way I know is in the registry, but I haven't done that since XP, I think. W10 is a whole 'nother animal.
There are tons of threads here on this, and all the ones I've read say it's a problem and don't even attempt it. I guess I don't understand why you need to do this? The corrupt account has been deleted, and everything is working correctly now, right?

lrw said:

I don't see any devices listed. Hopefully that is good.

Yep. The machine is not (or no longer) tied to your MS account.

lrw said:

Yes, everything is working well now, only one account. I just like as clean a system as practical, so getting rid of that old directory would be nice.

Cheers,
lrw

Glad to hear it's all working well now. Please go ahead and mark the thread as solved. Cheers!