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Microsoft has some security measures in place to prevent slow add-ins from running inside Outlook. The issue is however that in many cases add-ins without fault are mistakenly marked as slow and disabled by Outlook, and if this is not immediately corrected when it first happens, Outlook may permanently disable them with no easy way to re-enable them.
Solution 1
To make sure that Outlook will always load the Nimbus add-in, please perform the steps bellow:
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Under Add-ins in Outlook (File > Option > Add-ins > COM Add-ins - Go) you will see the current load behavior of the particular add-in. The load behavior of the add-in should be set to "Load at Startup" like this:
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Solution 2
If instead the load behavior is "Unloaded", then follow these steps:
1. Change Loading behavior manually
- Open your Registry Editor. To do this, open your Windows Start menu and type "regedit".
- Go to HKEY_CURRENT_USER\Software\Microsoft\Office\Outlook\Addins\Nimbus.Outlook2013AddIn
- Note what the LoadBehavior is set to. It will be a number like 0 or 1 or 3.
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- Close Outlook (and all other Office programs to be sure). Make sure the "OUTLOOK.EXE" process is not running in the Windows Task Manager
- Open the registry editor again. Double-click the registry key to edit it.
- Change the Load Behavior to "3." Close the registry editor.
- Re-open the registry editor to ensure "3" is still there.
- Open Outlook. The add-in should now load automatically at startup
42. Add-in Resiliency
If changing the LoadBehavior key still does not resolve it, there is another registry key you can adjust:
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