We have 2 2008 R2 dcs and added 2 2012R2 dcs but left all of the roles on the 2008 dcs.
We started having issues with exchange not moutning the dbs so we demoted the 2 - 2012 dcs and now the exch dbs wont mount at all..
I keep getting the following error when mounting it...
Error: An Active Manager operation failed. Error: The database action failed. Error: Operation failed with message: