Lightroom preview cache error and cloud syncing
"Lightroom encountered an error when reading from its preview cache and needs to quit."
After trying the usual solutions found by googling that issue I discovered the solution that worked for me and might help you if your files are being synced to the cloud.
I had this problem for the past few days after installing a new hard drive and reimaging my computer until last night when I discovered that Google Drive was syncing the Catalogue files as they were located on the laptops internal hard drive My Pictures folder. My photos are all on an external had drive and are synced to Google Drive.
I just had to stop the folder Lightroom in My Pictures from syncing to Google Drive and it stopped crashing and giving me that error.