I came across the following site today while troubleshooting a database in the Recovery Storage Group that wouldn't mount.
What to do when an Exchange Store won't mount
http://www.microsoft.com/technet/prodtechnol/exchange/2003/wontmount.mspx
The odd thing is that removing the database from the RSG and then re-adding it allowed me to mount the database without a problem.
Teo
