Please follow the below steps.
Go to Edit Menu<< Preferences
Click on General tab
Uncheck the Option " Show Add Photos to Screen"
Then, Go to Performance tab
Uncheck the Graphics Processor
Restart the Lightroom.
If the issue still appears, please create new Lightroom Catalog and try use it.
Let us know if that helps.
Thanks for responds. I'll have to say that telling me to go to the edit menu is funny given that opening such windows is that makes LR freeze. Neither the less, hotkeys!
I should have said that this is version 6.0. Not the latest I know, but it's worked fine for the past 2 months...
So the 'Show Add Photo..." seems to be a 6.2.1 feature, thus, there's nothing for me to do there.
I tried disabling GPU Accel before I posted the first time.
Now given that I can't click the 'New Catalog' button, I can't do that step. However this is a fresh install, and it wonderful asked me when I installed if I wanted to create one. So I did. For fun, I went and deleted that one and once again LR prompted me if I wanted to make a new one. So I did.
And I'm left with a still freezing LR. Sad Days.
Have you cleared the "Show Add Photos Screen" check box?
Or is it still selected?
Thought I'd give an update. The problem turned out to be a lose Hard Drive connection. The SATA cable became loose on one of my 4 drives. I rarely use the drive so I didn't notice and Windows 10 notifications for such an event is a bit obscure. Anyways, once I secured the connection so that the drive stop un/re -mounting. Lightroom worked again.