I recently went through the process of restoring one of my Domain Controllers and one of my Exchange Servers.
Once I had restored the Exchange Server I had to run an ESEUTIL /P on all my Mailstores in order for them to mount. I started with the Dept Heads Mailstore.
I then noticed that I was getting a lot of MSExchnageSA Errors in the event log.
I then tried mounting the Mailbox Store in the First Storage Group, but was unable to as I had not run the ESEUTIL /P on that database. once run (which took very little time as all it houses is the system mailbox) I mounted that Store and the errors seemed to stop coming in.
So I guess that it was linked to the System Mailbox not being mounted (makes sense after all).
So I know in the future that that Mailbox is the first to be mounted.
