"Lightroom encountered an error when reading from its preview cache and needs to quit. Lightroom will attempt to fix this problem the next time it launches".
You need to delete the Preview Cache for your Lightroom catalog.
It is located in the same folder as the Lightroom Catalog. The preview cache name ends with Previews.LRDATA and should be deleted. Do not confuse this with *.LRCAT, which should not be deleted.Below is the image of what it is named as
Location :- /Pictures/Lightroom on Mac.
Delete this Folder and restart Lightroom
Thank you! it worked! Thanks again!
Akash, You have helped me in the past and I have another problem, my LR CC cannot find the picture files on my iPhone to import them. Can you please help me? It was working fine earlier this morning and but not at all now. Thank you! Tammy