The dialogue for renaming a SAPUser currently requires the entry of a password.
However, if InActivePWD is set on the current SAPUser, this action fails.
The resulting SAPUser would have to be created in the same way as a newly created SAPUser without a password if InActivePWD is set on the "user to be renamed".
This is a product defect (34059).
Uncheck the option. Rename the SAPUser and check the option for the SAPUser again.
This will be fixed in a future release of the product. If you require this immediately corrected, please contact support for a hotfix referencing the defect ID 34059.