Hi, This is a problem I am facing with an Exchange Server 5.5 installation.My IS needs to be restarted from the services.msc on certain occassions - a senior colleague suggested that one of the reasons is when an attachment whose size is larger than our permitted limit arrives.He said that though a size limit is placed on attachment sizes , this issue will happen , because as a result of a bug in Microsoft Exchange 5.5 , this limit on attachment size is not enforced. But somehow , I am not convinced .So I have culled out the following from my Event Viewer's Application Log (in the same order in which they appeared in the Event Viewer's Application Log , top to bottom) : Source : MS Exchange SA Category : Monitoring EID : 1005 (MS Ex) Unexpected error <<0xc0040000 - The Microsoft Exchange Server computer is not available. Either there are network problems or the Microsoft Exchange Server computer is down for maintenance. Microsoft Exchange Server Information Store ID no: 8004011d-0526-00000000>> occurred. _________ ditto Unexpected error <<0xc0040000 - Network problems are preventing connection to the Microsoft Exchange Server computer. Microsoft Exchange Server Information Store ID no: 80040115-0514-000006bf>> occurred. ___________ Source : ESE97 Category : Logging / Recovery EID : 193 MSExchangeIS (2156) The database engine failed with error -510 while trying to log the commit of a transaction. To ensure database consistency, the process was terminated. Simply restart the process to force database recovery and return the database to a consistent state. ________________ Source : ESE97 EID : 130 Category : Logging / Recovery MSExchangeIS (2156) Error -1032 occurred while opening a newly created log file. ________________ Source : ESE97 EID : 145 Cat : General MSExchangeIS (2156) The database engine could not access the file called E:\exchsrvr\MDBDATA\edb.log. ________________ Any help will be greatly appreciated. Regards, Shyam Kumar Mangayil.