Mimecast for Outlook: "MAPI was Unable to Load the Information Service mcarchivemapi32.dll" Error

Document created by user.oxriBaJeN4 Employee on Sep 4, 2015Last modified by user.oxriBaJeN4 Employee on Oct 25, 2016
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When the Exchange folders are expanded, the error "An unexpected error has occurred. MAPI was unable to load the information service mcarchivemapi32.dll.  Be sure the service is correctly installed and configured." is displayed.




The MSMAPI directory located at "C:\Program Files\Common Files\System" does not contain any users in the Permission section of the Security tab (after right-clicking and selecting Properties for this folder). The following message is also displayed: "No permissions have been assigned for this object".




  1. Edit the Permissions to build the standard user list and permissions, by adding the "Authenticated Users" group (even though Windows will report that access is denied).
  2. Repeat this step for the 1033 subdirectory, and delete the mcarchivemapi32.dll file.
  3. Reinstall the mcarchivemapi32.dll file using the musepkg32.exe -i command:  C:\Program Files\Mimecast\Mimecast Outlook Add-In>musepkg32.exe -i.
  4. Restart Outlook.