Resiliency

DoNotDisableAddinList

Since 2013 the Office applications will automatically disable an add-in if it performs slowly.
The next time you open that application you will see a message bar appear telling you that an add-in has been automatically disabled.
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Selecting "View Disabled Add-ins" will display the Disabled Add-ins dialog box.
This will show you the name of the add-in that was experiencing problems.
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The "Always enable this add-in" button allows you to prevent this add-in from being automatically disabled in the future.
If the add-in is re-enabled and the performance problems continue then the Office program will experience performance problems.
If you select "Always enable this add-in" a registry key will be added for that application.

HKCU\Software\Microsoft\Office\16.0\Word\Resiliency\DoNotDisableAddinList 
DWORD - <progid> 
Value - Hex value indicating the reason the add-in was disabled 

If you want to remove an add-in from this list, go back to the Disabled Add-ins dialog box and choose "Disable this add-in".
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RestrictToList

link - learn.microsoft.com/en-us/microsoft-365/troubleshoot/group-policy/office-add-in-not-loaded 

No Add-ins loaded due to group policy settings for Office 2013 and Office 2016 programs.
If you then open the COM Add-ins dialog box by clicking Go, you cannot enable any of the listed add-ins.
When you select any add-in, the COM Add-ins dialog box displays the following text.
"The add-in you have selected is disabled by your system administrator."

The following registry key will disable all COM Add-ins

HKCU\Software\Microsoft\Office\16.0\Word\Resiliency\ 
DWORD - RestrictToList 
Value - 1 

AddinList

link - learn.microsoft.com/en-us/microsoft-365/troubleshoot/group-policy/office-add-in-not-loaded 

If you have blocked all COM Add-ins (using the RestrictToList) key you can provide a list of the add-ins that you will allow.
This allows you to specify which add-ins will be enabled, while everything else is blocked.

HKCU\Software\Microsoft\Office\16.0\Word\Resiliency\AddinList 
DWORD - <progid> 
Value - Indicating the load behaviour 

0 = The add-in is always disabled (blocked)
1 = The add-ins is always enabled
2 = The add-in can be manually enabled or disabled by the user