It seems like I run into this screen way too often:
While there can be a number of causes for this (in my case, it’s usually because there’s a script that popped up a dialog that you can’t see because it’s hiding behind that screen — pretty hard to click OK when you can’t get to the button), it’s always annoying because you have to wait for a long timeout period before it continues on to the desktop.
But in many cases, there is quicker way to get out of this. Press Control-Alt-Delete to get to this screen and then choose to “Sign out”:
Personally, I see this as “yet another reason” to turn off the first sign-in animation (FSIA), which I usually do via unattend.xml when first installing Windows 10:
<Description>disable firstlogon animation for win10</Description>
<Path>reg add HKLMSoftwareMicrosoftWindowsCurrentVersionPoliciesSystem /v EnableFirstLogonAnimation /t REG_DWORD /d 0 /f</Path>