If you had trouble updating the Enpass version from 5.6 to 6.0, follow these steps.
Download version 5.6, if you do not have the installer, in this link (Softpedia).
Synchronize with your previous backup in Dropbox, Google Drive or another Cloud.
Click File, and then click Backup.
Save the file in a safe place (remember the place).
Close the old Enpass 5.6.
Open the new Enpass 6.
Click on Import Backup
Locate the backup made in Enpass 5