It is almost 1 am. I’ve been resolving an Exchange2007 issues since 9 am. Everything is going as planned until I hit a strange behaviour. I couldn’t mount an Exchange 2007 database that was recently created. The error was: Error code: MapiExceptionADNotFound: Unable to mount database. To be more specific, the wizard created the database on AD but couldn’t mount it. After doing some troubleshooting I found out that Exchange was writing to one Domain Controller and reading from another, therefore, it wasn’t an Exchange issue, just needed to wait (or force) replication between DCs. Forced replication between the DCs on Active Directory Sites and Services and the database mounted instantly. Another thing that you can do is sit back and wait for it to replicate. I hope this helps you! If it does, please leave a comment.