Latest update to Lightroom Classic causes blank Window (Windows 10) fixed by updating LR/PS

[#1]

Closed down LR Classic CC normally last night / backed up.  On starting LR this morning a blank window appeared in middle of LR - it could be moved/resized but LR would not function at all.  Closing this blank window shutdown LR also.  I tried rebooting Win10 / different display screens (in case a graphics driver issue)/restarting LR several times - same issue each time.  Was about to try more drastic stuff such as deleting prefs etc but thought to check updates. 

Installing updates solved the issue so I suspect the blank window was a (non-functioning) window informing me of updates.

[#2]

Closed down LR Classic CC normally last night / backed up.  On starting LR this morning a blank window appeared in middle of LR - it could be moved/resized but LR would not function at all.  Closing this blank window shutdown LR also.  I tried rebooting Win10 / different display screens (in case a graphics driver issue)/restarting LR several times - same issue each time.  Was about to try more drastic stuff such as deleting prefs etc but thought to check updates. 

Installing updates solved the issue so I suspect the blank window was a (non-functioning) window informing me of updates.