Symptoms: 

An error occurs when selecting MIME Types from Management > Administration > Customization.

Explanation: 

The problem pertains to the database upgrade script: a missing check causes an unwanted row to appear in the mediaTypes and mediaTypeMappings tables.

Resolution: 

You can fix the issue by deploying the update to WorldServer 10.4.4, available on FTP.

If you cannot deploy it, contact the SDL Support Team:

• Log on to your "My SDL" Account.
• Log a support request via Support & Education Support. 

Note: 

All systems running WorldServer 10.4.4 and 10.4.5 should have this hotfix applied.