- 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. 

What can i do about it?

Below we list each option available to fix this issue:

Make sure you run Outlook as an Administrator when you enable the add-in (Right click - Run as Administrator)

When using CRM for Outlook, users can force the add-in to always be enabled. 

On the File tab, click <Slow and Disabled COM Add-ins>.

You'll see a list of add-ins. Click Always enable this add-in. 

If you have tried the solution referenced above and the add-in is still not loading when the application is opened, then it may be due to a registry setting. This registry setting determines how the add-in is loaded in the application. Follow the steps below to correct this registry setting.

Under Add-ins in Outlook 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".

1. Open your Registry Editor. To do this, open your Windows Start menu and type "regedit".
   
2. Go to HKEY_CURRENT_USER\Software\Microsoft\Office\Outlook\Addins\ZohoCRM_Plugin_for_Microsoft_Outlook_Addin
   
3. Note what the LoadBehavior is set to. It will be a number like 0 or 1 or 3. 
   

If the LoadBehavior key is anything other than "3" then follow these steps:

1. Close Outlook (and all other Office programs to be sure). Make sure the "OUTLOOK.EXE" process is not running in the Windows Task Manager
   
2. Open the registry editor again. Double-click the registry key to edit it.
   
3. Change the Load Behavior to "3." Close the registry editor.
   
4. Re-open the registry editor to ensure "3" is still there.
   
5. Open Outlook. The add-in should now load automatically at startup