There are a number of reasons why Mail Manager has been disabled or buttons are not enabled e.g.

•	The app version of Office that is pre-installed with Windows 10 is NOT compatible with Outlook add-ins like Mail Manager.

•	Outlook didn't exit correctly and disabled its Add-ins

•	An add-in is repeatedly slow to load (only applies to Outlook 2013, 2016 & 2019)

•	The Mail Manager Add-in is prevented from loading due to a user registry key issue (only applies to Outlook 2013, 2016, 2019 & Click-to-run installations)

•	Incorrect version of the .NET Framework see: Prerequisites

Step 1

Download and re-install Office 365

Windows 10 comes pre-installed with "The Office app for Windows 10" which is NOT compatible with Outlook COM add-ins. Therefore you need to download and reinstall Office by signing into your Office 365 account choosing Install Office

Step 2

Outlook has disabled Mail Manager

If Outlook exited unexpectedly it may have disable the Mail Manager Add-in. To re-enable:

a)	Select the File tab on the main Outlook window

b)	Select Options from the left-hand menu

c)	Select Add-Ins from the left-hand menu of the Outlook options window

d)	At the bottom of the window, change the ‘Manage’ dropdown to show Disabled Items and then click Go.

e)	If Mail Manager Addin is listed, select it and then click Enable.

f)	Go back to the ‘Manage’ dropdown and select COM Add-ins and then click Go.

g)	Ensure Add-in called: Mail Manager Addin is ticked then click OK

h)	Restart Outlook

For Outlook 2013, 2016 & 2019 also see: Take control of your Outlook 2013 add-ins

Step 3

Slow to load Add-ins

On the File tab, click Slow and Disabled COM Add-ins. You'll see a list of add-ins. Depending on the version of Outlook being used you may see different choices e.g. Always enable this add-in or Do not monitor this Add-in for the next 30 days.

Also see: Outlook’s slow add-ins resiliency logic and how to always enable slow add-ins

Step 4

The Mail Manager Add-in is prevented from loading due to a user registry key issue cause by uninstalling a newer version and installed an older version of Outlook. Use the Mail Manager Registry Checker to establish if there are any missing or incorrectly set registry keys

Step 5

If the issue persists, run a repair of Microsoft .Net Framework 4.6 (or 4.0 if this is installed instead).

Reboot the machine

Check the disabled items and COM-addins as per Step 1 above.

Step 6

Should none of the above resolve the problem, send Mail Manager support the diagnostics from the Microsoft Support and Recovery Assistant (SaRA)