Who is this article for?

IT staff who want to learn to troubleshoot the error 0x4005.

No elevated permissions are required.

1. Issue

If you encounter the following error message:

Error: 0x4005, (16389)
Function: MAPIInitialize
Context: Arup::DmLib::OasysMapi::CPostOffice::Initialise.

This error is most commonly caused by corruption within the Microsoft Office installation on your computer. Specifically, it indicates that the Outlook component of Office, which Mail Manager relies on to function correctly, is not operating as expected. Since Mail Manager requires a fully functional instance of Outlook to communicate and process emails, any issues or corruption in Outlook can lead to this error being displayed.

2. Resolution

To fix this, please perform and Online office repair on your Microsoft office.

• Microsoft's instructions to do this are linked here: How to perform an online office repair