4 Fixes for Outlook Add-In Missing or Not Working on Windows

Quick Tips

• Ensure you haven’t accidentally disabled your add-ins in Outlook.
• You can modify a few registry files to prevent Outlook from disabling add-ins automatically.
• Running the Office repair tool can also help fix various issues with Outlook, including this one.

Fix 1: Make Sure the Add-In Is Enabled

One possible reason for an Outlook add-in to disappear is if it has been disabled, either by the user or system administrator. If that’s the case, you can use these steps to restore the missing Outlook add-in on your Windows PC.

Step 1: Open the Microsoft Outlook app on your PC and click the File menu at the top-left corner.

Step 2: Select Options from the left pane.

Step 3: Switch to the Add-ins tab. In the Manage drop-down menu, select Disabled Items and click the Go button.

Step 4: Select the add-in you want to restore and click the Enable button.

Fix 2: Scan Outlook Data File

Issues with Outlook data files on your PC can also cause your add-ins to go missing or stop working. Fortunately, Microsoft includes a tool that can find and repair problematic Outlook data files automatically. Here’s how to run it.

Step 1: Press the Windows + E to open File Explorer and navigate to the following folder.

C:\Program Files\Microsoft Office\root\Office16

Step 2: Double-click the SCANPST.EXE file.

Step 3: Click Start to initiate the scan.

Step 4: If the tool finds any issues, click on Repair.

After completing the above steps, check if your add-ins work.

Fix 3: Modify Registry Files to Prevent Outlook From Disabling Add-Ins

At times, Microsoft Outlook may disable an add-in if it causes the app to run slowly or crash. If you don’t want that, you can modify a few registry files to stop Outlook from automatically disabling add-ins.

Step 1: Press the Windows key + R to open the Run dialog box. Type regedit in the box and press Enter.

Step 2: Type the following path in the address bar at the top and press Enter.

Computer\HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Addins

Step 3: Locate the add-in you don’t want Outlook to turn off and copy its name.

Step 4: Paste the following path in the address bar at the top and press Enter.

HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\16.0\Outlook\Resiliency\AddinList

Step 5: In the right pane, right-click anywhere on an empty spot and select New > String Value. Name it with the add-in key name copied earlier.

Step 6: Double-click the newly created string value, enter 1 in the text box and click OK.

Fix 4: Run the Office Repair Tool

If all else fails, you can run the Office repair tool on Windows to fix issues that may be causing the Outlook add-ins to misbehave. Here are the steps for the same.

Step 1: Press the Windows + R keyboard shortcut to launch the Run command. In the Open field, type appwiz.cpl and press Enter.

Step 2: In the Programs and Features window, select Microsoft Office Suite or Microsoft 365 and click the Change option.

Step 3: Select Online Repair and click the Repair button to continue.