Lr 11.3.1 Imports and Develop Module not working after update

[FJ12003CV]

I've used Lr since v3.0, currently on the Photography subscription using Lr Classic 11.3.1 on W10.    Catalogue backed up regularly and optimised regularly. 

Catalogue on a dedicated SSD, photos on 2 x WD Red 4TB local drives.  C-drive is an SSD. 

All drives verified by vendor's test apps as having no issues.  Peformance of all drives is as expected. 

AMD Athlon with 16GB.  All drivers up to date.

I use Canon cameras, mostly a 5D IV and shoot 95% RAW.  Lr is my main workhorse and I have an established workflow.  After updating to Lr 11.3.1 I have issues with the following:

1. Much, much slower then before the update.
2. The Develop module opens with a blank grey window despite an image being selected, and is unusable
3. Imports not actually importing after running the import wizard - irritating as my son's graduation images from a week ago are not importing and I have family and said son waiting.
4. Constantly writing data to xmp even if left running overnight and all day.
5. Folders in catalog look greyed out but when I click on them the images appear but can't edit in Develop.

Due to the above I uninstalled and re-installed today, and whislt slighty quicker, is still far slower than it was and the above proplems persist.  Basically, it's unusable.

[johnrellis]

Initial troubleshooting steps to rule out common problems:

1. Set Preferences > Performance > Use Graphics Processor to Off.

2. Make sure you have the latest graphics driver by going directly to the manufacturer's web site:

https://helpx.adobe.com/lightroom-classic/kb/troubleshoot-gpu.html#solution-4 

If you have an Nvidia chipset, make sure to install the Studio driver, which Nvidia tests and optimizes for stability with creative apps like Lightroom, rather than the Game Ready driver.

3. Try resetting LR's preferences:
https://www.lightroomqueen.com/articles-page/how-do-i-reset-lightrooms-preferences/

LR sometimes soils its preferences file, and resetting it can fix all sorts of wonky behavior. That article explains how to restore the old preferences if resetting doesn't help.