Hello, we just started getting this error message. Event ID 623 also 1025. We are running Outlook 2010 with MS Exchange 2003 SP2. We had multiple users that could not access their mailboxes for a few seconds, then everything was Ok. Anybody have experience with this type of issue?

Thanks,

Information Store (2980) First Storage Group: The version store for this instance (0) has reached its maximum size of 155Mb. It is likely that a long-running transaction is preventing cleanup of the version store and causing it to build up in size. Updates will be rejected until the long-running transaction has been completely committed or rolled back. 
Possible long-running transaction: 
SessionId: 0xBD531BA0 
Session-context: 0x00000000 
Session-context ThreadId: 0x00000508 
Cleanup: 1 

For more information, click 

An error occurred on database "First Storage Group\Mailbox Store (XXxxx)".
 Function name or description of problem: EcCategorizeMessage
Error: 0xfffffbd3 

Hi User...

Event Id 623 describes that ESE store has at its max size due to unresponsive transaction. Updates to the database were rejected till then the running transaction will be omitted....Go through this blog to get help in resolving the error 623..

https://mailsolutions.wordpress.com/2015/06/13/extensible-storage-engine-event-id-623/

Hope this will work