Generally speaking, an add-in is supplemental functionality that adds custom commands and specialized features to the Microsoft Office system programs. For example, smart tags, global templates, and XML Schemas are all add-ins or are referred to as "application extensions" because they extend the capabilities of an Office program. Some add-ins, such as COM add-ins, can extend functionality to several programs. This article describes how to view and manage the add-ins for your Office programs.In this article

View the installed add-ins

When you install the Microsoft Office system, several add-ins are installed on your computer.

  1. Do the following in these Microsoft Office system programs:

    Word, Excel, PowerPoint, or Access

    • Click the Microsoft Office Button button image, and then click Program Name Options, where Program Name is the name of the program you are in, for example, Word Options, and then click Add-ins.

    Visio, Outlook, Publisher, or InfoPath

    • On the Tools menu, click Trust Center, and then click Add-ins.
  2. View the add-ins and application extensions that are categorized as follows:
    • Active Application Add-ins Lists the extensions that are registered and currently running in your Office program.
    • Inactive Application Add-ins Lists the add-ins that are present on your computer but are not currently loaded. For example, smart tags or XML Schemas are active only when the document that references them is open. Another example is the COM add-ins that are listed in the COM Add-ins dialog box. If the check box for a COM add-in is selected, the add-in is active. If the check box for a COM add-in is cleared, the add-in is inactive. To learn how to open the COM Add-in dialog box, see the next section called .
    • Document Related Add-ins Lists template files that are referenced by currently open documents.
    • Disabled Application Add-ins Lists add-ins that were automatically disabled because they are causing Office programs to crash.

Identifying custom buttons and controls added to the Ribbon from add-ins

Add-ins and documents can add custom buttons and controls to the Ribbon. All custom controls in the Ribbon have a special ScreenTip that identifies the origin of the control. In this example, the control comes from RXDemo.xlsm, and is identified in the control's ScreenTip.

ribbon image

This way, you know where the custom controls are coming from and can then remove or update the document, global template, or COM add-in that is presenting the control. See the previous section to learn how to view installed COM add-ins.

Manage the installed add-ins

Managing add-ins can involve enabling or disabling an add-in, adding or removing an add-in, and making an add-in active or inactive.

  1. Do the following in these Microsoft Office system programs:

    Word, Excel, PowerPoint, or Access

    • Click the Microsoft Office Button button image, and then click Program Name Options, where Program Name is the name of the program you are in, for example, Word Options. Click Trust Center, click Trust Center Settings, and then click Add-ins.

    Visio, Outlook, Publisher, or InfoPath

    • On the Tools menu, click Trust Center, and then click Add-ins.
  2. In the Manage box, click the add-in that you want, and then click Go.
  3. Click the options that you want.

For information about enabling add-ins that were disabled by the Trust Center security system, see the next two sections.

How can the Trust Center help to protect me from unsafe add-ins?

Similar to macros and ActiveX controls, add-ins can be exploited by hackers to do malicious harm, such as spreading a virus. Because there are many add-ins from many sources other than Microsoft, there are specific criteria that need to be met before the add-in is considered trustworthy. The Trust Center enforces the following criteria:

If the Trust Center detects a potentially unsafe add-in that does not meet these criteria, the Trust Center disables the code by default, and the Message Bar appears to notify you of a potentially unsafe add-in or application extension.

message bar

If you click Options on the Message Bar, a security dialog box opens, giving you the option to enable the add-in. See the next section for how to make a secure decision before you click an option.

Note In Microsoft Office Outlook and Microsoft Office Publisher, security alerts appear in dialog boxes, not in the Message Bar. By default, Office Outlook allows any installed add-in to run. To change the default setting, see .

What should I do when a security warning asks if I want to enable or disable an add-in or application extension?

When a security dialog box appears, you can enable the add-in for just the current session by clicking Enable this add-in for this session only, or you can leave it disabled. You should enable the add-in only if you are sure it is from a trustworthy source.

Microsoft Office security options dialog box

Alternately, you can explicitly trust the publisher by clicking Enable all code published by this publisher. Doing so enables the add-in and allows any software by that publisher to be always trusted.

Microsoft Office Outlook

In Office Outlook, when the security dialog box appears, you can enable the add-in for just the current session by clicking Enable Application Add-in, or you can leave it disabled. You should enable the add-in only if you are sure it is from a trustworthy source.

Microsoft Office outlook security notice

Alternately, you can explicitly trust the publisher by clicking Trust all documents from this publisher. Doing so enables the add-in and allows any software by that publisher to be always trusted.

For more information about trusted publishers, see .

View or change the add-in security settings

Do the following in these Microsoft Office system programs:

Word, Excel, PowerPoint, or Access

  1. Click the Microsoft Office Button button image, and then click Program Name Options, where Program Name is the name of the program you are in, for example, Word Options.
  2. Click Trust Center, click Trust Center Settings, and then click Add-ins.
  3. Click the options that you want. These settings are not selected by default unless you work in an organization and your information technology (IT) administrator changed the defaults by using an administrator policy.
    • Require Application Add-ins to be signed by Trusted Publisher Select this option if you want the Trust Center to check for a digital signature on the dynamic-link library (.dll) file that contains the add-in. If the publisher has not been trusted, the Office program does not load the add-in, and the Message Bar displays a notification that the add-in has been disabled.
    • Disable notification for unsigned add-ins (code will remain disabled) This check box is available only if you select the Require Application Extensions to be signed by Trusted Publisher check box. In some situations, the dynamic-link library (.dll) file that contains the add-in might be unsigned. In these cases, add-ins signed by a trusted publisher are enabled, but unsigned add-ins are disabled silently.
    • Disable all Application Add-ins (may impair functionality) Select this check box if you don't trust any add-ins. All add-ins are disabled without any notification, and the other add-in check boxes are made unavailable.

      Note This setting takes effect only after you exit and then restart your Office program.

Visio, Publisher, or InfoPath

  1. On the Tools menu, click Trust Center.
  2. Click Add-ins.
  3. Click the options that you want. These settings are not selected by default unless you work in an organization and your information technology (IT) administrator changed the defaults by using an administrator policy.
    • Require Application Add-ins to be signed by Trusted Publisher Select this option if you want the Trust Center to check for a digital signature on the dynamic-link library (.dll) file that contains the add-in. If the publisher has not been trusted, the Office program does not load the add-in, and the Message Bar displays a notification that the add-in has been disabled.
    • Disable notification for unsigned add-ins (code will remain disabled) This check box is available only if you select the Require Application Extensions to be signed by Trusted Publisher check box. In some situations, the dynamic-link library (.dll) file that contains the add-in might be unsigned. In these cases, add-ins signed by a trusted publisher are enabled, but unsigned add-ins are disabled silently.
    • Disable all Application Add-ins (may impair functionality) Select this check box if you don't trust any add-ins. All add-ins are disabled without any notification, and the other add-in check boxes are made unavailable.

      Note This setting takes effect only after you exit and then restart your Office program.

Outlook

By default, Outlook allows any installed add-in to run. You can restrict Outlook to run only those add-ins that are digitally signed by applying the Warnings for signed macros; all unsigned macros are disabled setting to add-ins, as follows:

  1. On the Tools menu, click Trust Center.
  2. In the left pane, click Macro Security.
  3. Click Warnings for signed macros; all unsigned macros are disabled.
  4. In the left pane, click Add-ins.
  5. Select the Apply macro security settings to installed add-ins check box.