2003 information store stops over night around the same time

is there anything in the event logs of the server from around that time?
Im thinking either mailbox maintinance or a backup job might be kicking off and causing the service to fall over.

Cheers

Dave J

This is probably not the solution but I just thought I would throw this out.
I have also seen admins create backup jobs that stop the Exchange services to back the databases up and then incorrectly code or forget to restart the services.

If this is the case it is usually someone not familiar with how to backup Exchange.

Also as oldhammbc suggested, check the event viewer logs and post back here any questionable entries. Post the complete description along with the Event id at least.

I have a backup library that backs up exchange, But it just started happening in the last week.  So if it were the back up wouldn't it have done this before?  I have a ton of logs can I delete them?  That might clear it up but I don't know if I can delete logs on the fly like that.  Is there a speacial way to delete logs?

"So if it were the back up wouldn't it have done this before?"
Probably so but I just threw out this idea in case some other admin had modified the backup routine.

"I have a ton of logs can I delete them?"
What logs are they? Can you post a couple of the file names?
If they are Exchange transaction logs then NO.
If they are Exchange tranaction logs then these will get purged whenever you run a full ONLINE backup of the Exchange Information Store.
What program are you using to backup Exchange?
Some 3rd party apps require an Exchange agent to do this. Notice that this is not an Open File Agent. They are totally different agents.

I have veritas 9.1 for the back up and yes I have a exchange back up license.  
the logs are similar to this:  E000C3A0.log, E000C3A1.log, E000C3A2.log...etc...

Hey thanks everyone for your input ad great advice.  I have been quiet for a couple of reasons.  1.  I saw that the issue was partly due to the way I installed the exchange sp 2.  I have exchange 2003 standard and our information store was getting to compacity so I installed SP2 which expands the db size upto 75gb.  So I missed the part of SP2 by default opens it up to only 18gb...  this is where I had to create two registry keys unlocking the ability to expand to 75gb.  Then I monitored it.... worked fine for a bit....  2.  Now it is happening again but this time I do believe its the backups that are stopping my information store.  I noticed yesterday that when veritas goes through its verify stage this is when the informations store gets screwy.