Restore fails with "Error writing to database Duplicate entry for key 'mdl_courcomp_usecou_uix'"

Enable completion tracking on the site (Home ► Site administration ► Advanced features) and the course (Home ► My courses ► Miscellaneous ► Course ► Edit settings) Create an assignment (you can have completion set to "Students can manually mark the activity as completed") Set up course completion to depend on the completion of assignment Login as an enrolled user, and mark that assignment as complete Run cron (possibly twice), ensure that course is marked as completed for this student Create a backup of the course with user course completion data Restore it in the same course While it is restoring, run php admin/cli/cron.php to force a cron run. Make sure there are no errors Check course completion report for the restored course and make sure that courses are marked as completed when needed and the completed time is the same as it was in original course and not the time of restore