Microsoft KB Archive/256879

= XADM: Mbclean Stops Unexpectedly Because of Memory Corruption =

Article ID: 256879

Article Last Modified on 10/26/2006

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APPLIES TO


 * Microsoft Exchange Server 5.5 Service Pack 3

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This article was previously published under Q256879





SYMPTOMS
During normal operation the Microsoft Exchange Server Mailbox Manager service (Mbclean.exe) may stop unexpectedly with an access violation. If the correct Microsoft Windows NT and Exchange Server debug symbols are installed, the resulting Dr. Watson log may contain a stack dump similar to the following:

FramePtr RetAddr   Param1   Param2   Param3   Function Name 08c9ec3c 00401be2  02e30ffd 08c9ec60 0000003b MBCLEAN!ulGetName+0x2d 08c9ed60 004021b5  02e36ff0 77f04f32 08c9f750 MBCLEAN!CProcessed::IsAlreadyDone+0x42 08c9f640 00406824  02e3cd90 00414348 02e26ff0 MBCLEAN!hrWalkUsersInContainer+0x2f5 08c9f684 0040629d  00000000 00000000 02e26ff0 MBCLEAN!ProcessOneContainer+0x474 08c9f6f4 00405be6  02e38d90 08c9f750 02e26ff0 MBCLEAN!ProcessContainer+0xcd 08c9fc1c 004096bc  08c9fc54 7ffdf000 08c9fd74 MBCLEAN!StartMailboxCleanup+0x566(...) 08c9fc40 6722aa3b  08c9fdac 9e72b964 01bf7fa9 MBCLEAN!TimerAPCProc+0x25c 08c9fd1c 77f1ce85  00000002 08c9fd44 00000001 NTDLL!RtlpDebugPageHeapCreate+0x384 00000023 00000000  00000000 00000000 00000000 KERNEL32!WaitForMultipleObjectsEx+0x10b



CAUSE
This issue can occur because Mbclean records the names of all of the mailboxes that it processes (in a temporary file in the Mbxman folder called the ProcessedMailboxes.txt file) before all of the mailboxes have been processed. When data is read out of this file, it does not set a terminating NULL at the end of the character string in the memory buffer. Thus all later references to this character string may exceed the range of the string itself, which can cause an access violation if the next memory block is not accessible.



RESOLUTION
To resolve this problem, obtain the latest service pack for Exchange Server 5.5. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

191014 XGEN: How to Obtain the latest Exchange Server 5.5 Service Pack



STATUS
Microsoft has confirmed that this is a problem in Microsoft Exchange Server version 5.5 Service Pack 3. This problem was first corrected in Exchange Server 5.5 Service Pack 4.

Keywords: kbhotfixserver kbqfe kbbug kbexchange550presp4fix kbexchange550sp4fix kbfix kbqfe KB256879

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