Mailbox exporting and AV issues – BA1771 (MAPI_W_PARTIAL_COMPLETION)

Hi all,

Over the years we’ve seen issues where AV programs flag certain emails as containing a virus, and prevent access to those emails. Recently we’ve seen this happen more, so it deserves a public explanation.

We’ve found that when AV programs detects viruses, they flag the actual email itself, preventing any application from accessing the email. This means that our mailbox export application will also fail. The line in the Exmerge report is:

Error copying message with subject 'Movie Times' in folder '\Deleted Items'. (MAPI_W_PARTIAL_COMPLETION)

Once flagged, the email cannot be accessed, even if you uninstall or stop the AV program. Even Outlook Web Access won’t be able to read the email – it may appear in the email list, but if you open the email, you may be an Internal Server Error message. Because this appears to be blocked at the Exchange level, any applications that sit “above” Exchange – such as BackupAssist – won’t be able to access the message.

The solution to this is to actually delete these messages – depending on your AV program, you should be able to purge these messages from the system. If this is not possible or you don’t wish to do it, you can usually work around this by telling BackupAssist to exclude exporting messages in certain folders, such as Junk E-mail, SPAM, Deleted Items. To do this, make sure you’re running a recent version of BackupAssist, and go to your backup job, and click the options tab (the bottom tab in the left hand column, either called NTBackup options or Exmerge options). Locate the “Folders to exclude” option and activate this feature.

If anyone has further issues, please contact us or post a reply to this blog message.



2 thoughts on “Mailbox exporting and AV issues – BA1771 (MAPI_W_PARTIAL_COMPLETION)”

  1. I’m getting 2384 non-fatal errors encountered of this type so there must be another reason besides av flagging these messages.


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