Could you please try creating a new catalog and check if you have similar issues.
You could Roll back to the Previous version if required .Please refer Instructions to roll back to a prior update version
Many, many people have reverted back to LR CC 2015.1.1 / 6.1.1, the last stable release for many people. See here for instructions: Instructions to roll back to a prior update version. You won't lose any changes to your photos or catalog.
Adobe has apologized for all the problems with 2015.2 and 2015.2.1: Lightroom 6.2 Release Update and Apology, Lightroom 6.2 Import Update. Instead of wasting time troubleshooting, just revert and wait for Adobe to clean up the mess.