When my lightroom opens up it says, "Lightroom encountered an error when reading from a previous cache and needs to quit". don't now what to do!
Please delete the Preview Cache.
To delete the preview cache, do this:
1. Quit Lightroom.
2. In your Operating System, locate your Lightroom catalog. Typically catalogs are in /Pictures/Lightroom on Mac and My Pictures\Lightroom on Windows.
3. Find the folder whose name ends with "Previews.lrdata" and delete it.
Moved to Lightroom forum.