When you repair a catalog in the Elements Organizer, the progress bar doesn't move for a long time during the "Checking catalog for errors" stage. Sometimes, the progress dialog box turns white, and the Elements Organizer appears to freeze.
Wait for the repair process to complete. Your catalog most likely contains a large number of photos and other media (for example, 5000 or more). Large catalogs take more time to check for errors.
When you repair a large catalog, it's possible that the Elements Organizer doesn't have enough system resources to update the progress bar. The larger the catalog is, the longer the delay before the progress bar is updated.
If you click Cancel to end the repair process, it can take ten or more seconds to complete any pending operations.