I'm unable to open up Lightroom 5, I get this message in a pop up box: "Lightroom encountered an error when reading from it's preview cache and needs to quit" Underneath that is "Lightroom will attempt to fix this problem the next time when it launches." It hasn't, what should I do? Thanks Shawn (Irish Se7en) .
Can you try to rename (not delete!) the folder named "YOUR_CATALOG_NAME Previews.lrdata" and restart Lightroom?