users suddenly started getting following error " when they try to send out a email to internal or external users This message could not be sent. Try sending the message again later, or contact your network administrator. Error is [0x80004005-00000000-00000000]. " checkedthe eventviewer on exchange ..foundtons of following events..event ID 1022"Logon Failure on database "First Storage Group\Mailbox Store (XYZ-Server)" - Windows 2000 account XYZ\testuser; mailbox /O=XYZ/OU=ABC/cn=Recipients/cn=cstier3... Event ID 1025 "An error occurred on database "First Storage Group\Mailbox Store (XYZ-Server)". Function name or description of problem: EcGenerateNDR: Error: 0xfffff9bf Error: -1069" Event ID-623nformation Store (5876) 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. EVENT ID-9791Possible long-running transaction: SessionId: 0x7FD38220 Session-context: 0x00000000 Session-context ThreadId: 0x00000734 Cleanup: 1 For more information, click Cleanup of the DeliveredTo table for database 'First Storage Group\Mailbox Store (XYZ-Server)' was pre-empted because the database engine's version store was growing too large. 0 entries were purged. I rebooted the box and it fixed the issueand couldnt find anyting substantial cause of the issue.. I have exchagne sp2 enterprise running on windows 2003 sp1 Any help would be appreciated.. -D

Hi,This might help explain what happened:http://www.microsoft.com/technet/support/ee/transform.aspx?ProdName=Exchange&ProdVer=6.5.0000.0&EvtID=623&EvtSrc=ESE&LCID=1033Leif

Please scan the exchange server using Best Practises Analyser Vinod |CCNA|MCSE 2003 +Messaging|MCTS|ITIL V3|

Hi,Hope the below article can help you on this issue:http://msexchangeteam.com/archive/2006/04/19/425722.aspxThanksAllen