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Could not load file or assembly Microsoft.Office.Interop.Outlook

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Posted on by UG Leader

When trying to send an invoice using Outlook, the following message is thrown:

A call to Microsoft.Dynamics.Nav.Integration.Office.Outlook.IOutlookMessage.CanInitializeOutlook failed with the message: Could not load file or assembly Microsoft.Office.Interop.Outlook, Version=15.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c of one of its dependencies. Access denied.

When running NAV as admin, the error is not thrown and the invoice can be sent without issues.

We are using Dynamics NAV 2017 (10.0.16177)

What could be the issue?

  • Ghetz Profile Picture
    Ghetz 2,977 on at
    RE: Could not load file or assembly Microsoft.Office.Interop.Outlook

    Same problem in NAV 2018. Happens often when trying to send PO by email

  • Henkvv Profile Picture
    Henkvv 5 on at
    RE: Could not load file or assembly Microsoft.Office.Interop.Outlook

    Anyone found another solution?

    I've the same issue, only one user (but not everybody uses this function).

    Adding security access to the office.dll file did not work.

    Added also to the file in the Microsoft Dynamics NAV\90\office.dll file.

    We use Nav2016 and Office 2010.

  • IT Wine Guy Profile Picture
    IT Wine Guy 5 on at
    RE: Could not load file or assembly Microsoft.Office.Interop.Outlook

    I'm seeing this in my environment as well, but the users in question are already added to that .dll file mentioned. We're on NAV 2016 9.0.44974.0, and using Outlook 2016 64 bit (16.0.12130.20272). Only a few of my users are affected, and it seems random. It'll work for a couple of days for them and then suddenly stop working for an entire day. 

  • Suggested answer
    Community Member Profile Picture
    Community Member UG Leader on at
    RE: Could not load file or assembly Microsoft.Office.Interop.Outlook

    I was able to fix the issue by analyzing the fusion logs.

    The issue was not with the dll in the error message, but with the dll called office.

    "C:\Windows\assembly\GAC_MSIL\office\15.0.0.0__71e9bce111e9429c\office.dll"

    When adding the user under security of this file, the issue was resolved.

  • Community Member Profile Picture
    Community Member UG Leader on at
    RE: Could not load file or assembly Microsoft.Office.Interop.Outlook

    In my case, Outlook does not have to be running as administrator, only NAV.

  • RE: Could not load file or assembly Microsoft.Office.Interop.Outlook

    I am experiencing the same thing.  Do not have an answer yet but have seen that if you open Outlook and NAV as 'Run As Administrator' that is a viable workaround. Hope this helps short-term. 

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