Please turnoff the GPU from the Preferences and see how it works.
Click on Edit Menu from the top menu bar
Click on Preferences (Shortcut Ctrl+)
Click on the Performance tab
Uncheck the Use Graphics Processor
Restart the Lightroom and see how it works.
Let us know if it helps.
LR also locks up when I try to do that. I click on the check box and the software immediately stops responding.
Manually disable the graphics processor in Lr
- Navigate to C:\Users\Username\AppData\Roaming\Adobe\Lightroom\Preferences\Lightroom 6/CC Preferences.agprefs (Appdata is the hidden folder)
- Right Click on the Lightroom 6 Preferences.agprefs>> Open with Notepad
- Change the following line: useAutoBahn = true to the following useAutoBahn = false
- Save and close the file Lightroom 6 Preferences.agprefs
- Launch Lightroom CC/6 again.