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If the Outlook client starts behaving oddly, one of the first things to do is see whether add-ins are causing the problem. Here’s how to disable them so you can tell if they’re the issue.

What are Add-Ins?

Add-ins are extra bits of functionality that software providers create to hook their application into Outlook. You can install add-ins yourself by opening Outlook and clicking Home > Get Add-ins, which will show you some of the add-ins available to you.

The Get Add-ins button

However, most add-ins are installed automatically when you install a piece of software on your computer. You may never use the add-ins, or even be aware that they’re there, but they aren’t (usually) malware or anything nasty. They’re intended to make it easier for you to use a product. For example, when you install Adobe’s Acrobat PDF reader, it installs an Outlook add-in that lets you make PDFs out of emails.

There’s usually no need to remove add-ins, but if Outlook starts behaving oddly—especially if it freezes, crashes, or refuses to open—then disabling the add-ins will tell you if they’re the problem.

How to Disable All Add-Ins

Troubleshooting is all about finding the cause of a problem. The best way to do this is to gradually narrow down the possible issues until you’re left with just the cause of the problem. In the case of Outlook problems, this means disabling all the add-ins and, if the problem goes away, re-enabling the add-ins one by one to identify which one is causing the problem. This is particularly true if Outlook is encountering problems at startup.

The easiest way to disable all of the add-ins at once is to open Outlook in Safe Mode. This disables all the add-ins but doesn’t change anything else, so if one (or more) of the add-ins is causing the problem, everything will work as expected in Safe Mode. There are several ways to open Outlook in Safe Mode, depending on what version of Outlook and which version of Windows you’re using. There are a couple of methods that generally should work across all the combinations of supported versions of Outlook and Windows, but if these don’t work then search online for your particular combination.

Method One: Hold the Ctrl Key While Launching Outlook

This works whether you click an icon on your taskbar, desktop, or from the Windows menu. Hold down the CTRL key on your keyboard while clicking the Outlook icon (or double-clicking if your icon is on the desktop). A confirmation message will be displayed.

The Safe mode confirmation dialogue

Click “Yes” to open Outlook in Safe Mode.

Method Two: Use the Run Dialog or Windows 10 Start Menu

In Windows 10 press the Windows key, or in Windows 7 or 8 press the Windows key + R. In Windows 10 this will bring up the Windows menu where you can type commands directly, and in Windows 7 or 8 this will bring up the Run dialog, where you can also type run commands. Either way, type “outlook.exe /safe” (without the quote marks) and then hit Enter. This will bring up the Profile Chooser.

The Profile chooser dialogue

Choose the profile you want to open (for most people there will only be a single “Outlook” profile to choose) and then click “OK.” This will open Outlook in Safe Mode.

Whichever method you choose, Outlook will be open in Safe Mode. The name of the program in the header bar will change from “Microsoft Outlook” to “Microsoft Outlook (Safe Mode).”

Outlook header bar showing Safe Mode text

All of the add-ins will be disabled, EXCEPT some core Microsoft Office add-ins. These are very unlikely to be the cause of an Outlook issue, but you can disable them manually once Outlook is open. Next time you open Outlook as usual (i.e., not in Safe Mode), the add-ins will be enabled again, unless you’ve manually disabled them.

How to Disable Individual Add-ins

Starting in Safe Mode will tell you if one of your add-ins is the problem, but if you want to disable a single add-in—such as one that’s just been installed or a core Microsoft add-in that isn’t disabled in Safe Mode—you can do that too. Click File > Options, and then click the “Add-Ins” category on the left.

The Add-ins option

This will open the Add-ins section. To enable or disable add-ins, make sure that “COM Add-ins” is selected in the dropdown (it’s the default, so you shouldn’t need to change it) and then click “Go.”

The Go button for managing add-ins

This opens up the COM Add-ins dialogue, where you can enable or disable add-ins.

The COM Add-ins dialogue

Enabling and disabling is a tick-box exercise—a tick means the add-in is enabled; no tick means the add-in is disabled. To disable an add-in, untick it and then click “OK.”

The COM Add-ins dialogue with an add-in and the OK button highlighted

Important: Make sure that you don’t click “Remove.” This will uninstall the selected add-in, not disable it!

When you go back into File > Options > Add-ins, the add-in you disabled will be visible in the disabled add-ins section.

The Add-ins option showing a disabled add-in

The add-in will remain disabled until you enable it again. Test to see if your problem occurs when the add-in is disabled; if it does, keep disabling your add-ins one by one until you find the culprit.

How to Enable Individual Add-ins

Once you’ve worked out what add-in is causing the problem (if any of them are), you can re-enable any other add-ins that you disabled. Enabling individual add-ins is as simple as disabling them: click File > Options > Add-Ins, make sure that “COM Add-ins” is selected in the dropdown, and then click “Go” to open up the COM Add-ins dialogue.

Tick the add-ins you want to enable and then click “OK.” You might have to restart Outlook for the add-ins to load, and it’s generally a good idea to do that anyway to make sure everything is working correctly.

You can disable and enable add-ins whenever you’re troubleshooting an Outlook problem. They’re not always the cause, but if Outlook has been working fine and then a problem occurs after a new add-in has been installed, it’s a good place to start looking.

Profile Photo for Rob Woodgate Rob Woodgate
Rob Woodgate is a writer and IT consultant with nearly 20 years of experience across the private and public sectors. He's also worked as a trainer, technical support person, delivery manager, system administrator, and in other roles that involve getting people and technology to work together.
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