For activating the Add-in manually please refer to How to activate the Microsoft Office Add-ins?
The following article outlines the resolve when the Document Manager Addin for Microsoft Outlook keeps disabling after activating.
Why does this happen?
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:
Be an Administrator:
Make sure you run Outlook as an Administrator when you enable the add-in (Right-click and select Run as Administrator).
Force Outlook to always enable the add-in:
When using CRM for Outlook, you 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.
Changing the Load Behavior:
If you have tried the solution 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.
In Outlook, File, Options, 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.
2. Follow the steps below if the Load Behavior is set to Unloaded.
CAUTION: We recommend that registry key changes are made in consultation with an IT professional.
a. Open your Registry Editor. To do this, open your Windows Start menu and type regedit.
b. Go to HKEY_CURRENT_USER\Software\Microsoft\Office\Outlook\Addins\HsOfficeAddIn.HandiSoftOfficeAddIn.
c. 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:
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.
d. Open Outlook. The add-in should now load automatically at startup.
See this MSDN article for more information about the LoadBehavior values.
Check the Trust Centre settings.
In Outlook go to File, Options, Trust Center, click Trust Center Settings..., select the Macro Settings tab.
Enable all macros should be selected.
Apply macro security... should NOT be selected.
Add-in Resiliency:
If changing the LoadBehavior key still does not resolve it, there is another registry key you can adjust. Microsoft keeps track of what it decides are problematic add-ins in the registry via the Resiliency key. The path to this key varies by Office version:
Office 2016: HKEY_CURRENT_USER\SOFTWARE\Microsoft\Office\16.0\Outlook\Resiliency
Office 2013: HKEY_CURRENT_USER\SOFTWARE\Microsoft\Office\15.0\Outlook\Resiliency
Office 2010: HKEY_CURRENT_USER\SOFTWARE\Microsoft\Office\14.0\Outlook\Resiliency
In general, you should look in the latest number present in your registry for your latest Office installation. If Office thinks an add-in has an issue it will ask if you want to disable the add-in. If you click Yes then it will be added to the DisabledItems key:\
2. Once an add-in has been placed in the DisabledItems key, Office will not let the add-in load by default. To solve this first make sure Outlook is closed and then delete all the keys in DisabledItems.
CAUTION: This will re-enable every disabled add-in.
3. You must add a DWORD value to this key with the name of HsOfficeAddIn.HandiSoftOfficeAddIn and value of 1 as shown in the screenshot above
4. Then start Outlook again and the add-in should start.
5. To prevent Outlook from disabling the add-in again, it must be added to the DoNotDisableAddinList.
If the Addin is still not holding please run a repair on your Outlook. See this article on running a repair on Office products.