When recreating AD Sync: "cannot change synchronization interface because data exists in this domain"

I am attempting to re-create an AD sync project over 5 domains.  

When I attempt to use the wizard to create the base objects for 3 of the 5 I receive the error "cannot change synchronization interface because data exists in this domain".  However, 2 of the domains I am able to create the base object for without any issue.

If I manually create the base objects for the troubled domains the projections do not work but I can successfully run the initial synchronization workflow. 

Digging further I found that in Manager, in the AD domain section,  the domains I am unable to create the base object for are marked as "No Synchronization"  and If I try to manually change the entry here I am met with a very similar error

Any help on clearing this up would be greatly appreciated. 

-Aaron