To fix this issue, please do the following steps:
Run REGEDIT.
Find HKEY_LOCAL_MACHINE \ SOFTWARE \ Classes
Find the entry "confDTMcom.confDTMcom.1"
Remove the entry "confDTMcom.confDTMcom.1"
Then you will be able to update the DTM catalog in Unity.
Run REGEDIT.
Find HKEY_LOCAL_MACHINE \ SOFTWARE \ Classes
Find the entry "confDTMcom.confDTMcom.1"
Remove the entry "confDTMcom.confDTMcom.1"
Then you will be able to update the DTM catalog in Unity.