I am new to Lightroom and feel like cancelling it !! I have exactly the same problem but further more I cant get the top menu to work either. I have LR Classic version 8.2.1. Am running it on a Mac 1TB , 16GB RAM. So frustrating that its now frozen. Restarting computer doesnt help. Is there a storage capacity issue with my LR Cat which is using 23.5GB. Of this the Smart Previews is taking up 13.81GB and the Previews takes up 7.25 GB. I have downloaded 66,000 photos on Lightroom. Love someone to solve this please !
As Roeloff has suggested, the problem in develop is likely related to the Windows GPU driver. Either it is not up to date from the GPU mfg. or the hardware is not compatible with LR. The GPU is used to supplement the CPU by providing an additional computational core for certain LR Develop functions. A bad or incompatible GPU driver and Windows hangs or crashes.
With a Mac, this is not going to be a problem IF your OS has the latest patches from Apple. You should be running MacOS v 10.14.4. Unlike Microsoft, Apple controls the hardware and the software.
Your catalog file (the one with the .lrcat extension) should not be 23 GB This suggests problem with the catalog file itself. With 1TB Primary drive working storage and frees space should not be a problem, but you should never let it get below 1GB
If you can open LR and get the menu, open the Help sub menu and post the contents of {Help}{System Info...} in your next reply. We should be able to diagnose any hardware issues.
With a 23GB catalog file (.lrcat), I would suggest that you use the "Export as a Catalog" option to copy all of the imported images to a new catalog file. This will copy all of the good data about these images to a new clean catalog that should be smaller than 23GB) This new catalog file should then become your new master catalog file.
Unless you are using the Smart Previews for work when away from the Primary images files, you do not need to Smart Previews folder. You can turn off creating these on import and delete the Smart Previews folder.
Regular previews need to be managed with the size and retention period setting in the file handling tab of Catalog Settings. With LR closed you can deleted the Previews folder and LR will create a new empty one the next time LR opens that catalog file. LR will then proceed to build new previews just for those images that LR actually needs previews for. This will take a little longer when you open an image file for the first time but the result is a much smaller Previews folder.