Troubleshoot Add-In Startup Issues

25th October 2020


This article describes the procedure to be executed in order to troubleshoot an installation which can’t start Outlook with the CMS Add-In client being active. Follow the below steps in a sequential order.


After completing each steps, restart Outlook and try to re-enable the Add-In (File > Options > Add-ins > Manage > Go… )


1. Requirements Validation

Check that the QuickOnline CMS Add-In dependencies are installed:
a. Microsoft .Net Framework v4.5.1 or above
b. Microsoft VS Tool for Office Runtime (here)

2. Disable all others Add-In to identify potential conflicts

Open Outlook and navigate to “File > Options > Add-ins > Manage > Go… ” and disable all Outlook Add-In except the QuickOnline CMS Add-In.

3. Uninstall & reinstall the QuickOnline CMS Add-In

Open the “Add or Remove Programs” console, select the QuickOnline CMS Add-In and click “Uninstall”. Download the latest version from the Add-In (here) and re-install the Add-In.

4. User Account & Outlook Profile related issue

Log on the PC with another user to create a fresh Outlook profile on the machine and start the CMS Add-In.

5. Enable Advanced Outlook Debug Messages

Enable advanced VSTO debug by creating the below environment variables
a. VSTO_SUPPRESSDISPLAYALERTS=0
b. VSTO_LOGALERTS=1
In Outlook browse File > Options > Advanced:
c. Developers > Show Add-in user interface errors
d. Other > Enable troubleshooting logging (requires restarting Outlook)

Enable Advanced Fusion logging

Enable advanced Fusion logs:
Open a CMD as an administrator and run the following:
reg add “HKLM\Software\Microsoft\Fusion” /v EnableLog /t REG_DWORD /d 1 /f
reg add “HKLM\Software\Microsoft\Fusion” /v ForceLog /t REG_DWORD /d 1 /f
reg add “HKLM\Software\Microsoft\Fusion” /v LogFailures /t REG_DWORD /d 1 /f
reg add “HKLM\Software\Microsoft\Fusion” /v LogResourceBinds /t REG_DWORD /d 1 /f
reg add “HKLM\Software\Microsoft\Fusion” /v LogPath /t REG_SZ /d C:\FusionLog\

if not exist “C:\FusionLog\” mkdir C:\FusionLog
Collect the CMSAddin and CMSAddinCore logs under the following directories:
– C:\FusionLog\Default\OUTLOOK.EXE
– C:\FusionLog\NativeImage\OUTLOOK.EXE

To disable the fusion logging, open a CMD as an administrator and run the following:
reg delete “HKLM\Software\Microsoft\Fusion” /v EnableLog /f
reg delete “HKLM\Software\Microsoft\Fusion” /v ForceLog /f
reg delete “HKLM\Software\Microsoft\Fusion” /v LogFailures /f
reg delete “HKLM\Software\Microsoft\Fusion” /v LogResourceBinds /f
reg delete “HKLM\Software\Microsoft\Fusion” /v LogPath /f

6. Base components repair attempts

Perform a repair or upgrade of .NET framework
Perform a repair install or upgrade of Microsoft Office

Troubleshoot Add-In Startup Issues

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