I am getting similar errors when trying to Log in.

There is an error Dialog that pops up on Login.  If I close the Dialog QB closes.

But If the Dialog Stays open QB works normally.

I have 8 installations (Win 10)  and only 3 of these have the problem. ( Just added one today after we upgraded him to 16G RAM)

Reinstalling had no effect.

Type of user permissions no effect.

This is a problem because I cannot login to manage the Backups.