On the Edit Users area after selecting a user, when enabling Subversion login I see the following error:
Failed to save mailbox : A password must be entered when enabling SVN for a user
The only way around the error is to enter a password for the user into the "Set To..." entry box at the top and then save the changes.
I am running 3.96 Virtualminpro and 4.9 Subversion repositories.
I have attached some images for documentation.