Please go to the location where you have saved your catalog.
By default the Catalog is saved in the pictures folder inside the fodder named Lightroom.
Open the Lightroom folder and you will find a folder by the name of "Lightroom 5 Catalog Previews.lrdata"
move this folder to desktop and restart the Lightroom
I have two catalog folder for lightroom 5 should I move them both to the desktop?
all the lightroom 5 folders that said previews are now onto the desktop and I tried to restarted the program twice, it still doesn't launch....why is this still happening? I mean worse comes to worse I have lightroom 4 I can still use but some features in 5 are better....
Please check the location of the Catalog that is being open in Lightroom 5.
Are you using mac or windows ?