Validate and troubleshoot issues with your manifest

You may want to validate your add-in's manifest file to ensure that it's correct and complete. Validation can also identify issues that are causing the error "Your add-in manifest is not valid" when you attempt to sideload your add-in. This article describes multiple ways to validate the manifest file and troubleshoot problems with your add-in.

Validate your manifest with the Yeoman generator for Office Add-ins

If you used the Yeoman generator for Office Add-ins to create your add-in, you can also use it to validate your project's manifest file. Run the following command in the root directory of your project:

npm run validate

Animated gif that shows the Yo Office validator being run at the command line and generating results that show Validation Passed


To have access to this functionality, your add-in project must have been created by using Yeoman generator for Office Add-ins version 1.1.17 or later.

Validate your manifest with office-addin-manifest

If you didn't use the Yeoman generator for Office Add-ins to create your add-in, you can validate the manifest by using office-addin-manifest.

  1. Install Node.js.

  2. Run the following command in the root directory of your project. Replace MANIFEST_FILE with the name of the manifest file.

     npx office-addin-manifest validate MANIFEST_FILE


    If running this command results in the error message "The command syntax is not valid." (because the validate command is not recognized), run the following command to validate the manifest (replacing MANIFEST_FILE with the name of the manifest file):

    npx --ignore-existing office-addin-manifest validate MANIFEST_FILE

Validate your manifest against the XML schema

You can validate the manifest file against the XML Schema Definition (XSD) files. This will ensure that the manifest file follows the correct schema, including any namespaces for the elements you are using. If you copied elements from other sample manifests double check that you also include the appropriate namespaces. You can use an XML schema validation tool to perform this validation.

To use a command-line XML schema validation tool to validate your manifest

  1. Install tar and libxml, if you haven't already.

  2. Run the following command. Replace XSD_FILE with the path to the manifest XSD file, and replace XML_FILE with the path to the manifest XML file.

     xmllint --noout --schema XSD_FILE XML_FILE

Use runtime logging to debug your add-in

You can use runtime logging to debug your add-in's manifest as well as several installation errors. This feature can help you identify and fix issues with your manifest that are not detected by XSD schema validation, such as a mismatch between resource IDs. Runtime logging is particularly useful for debugging add-ins that implement add-in commands and Excel custom functions.


The runtime logging feature is currently available for Office 2016 desktop.


Runtime Logging affects performance. Turn it on only when you need to debug issues with your add-in manifest.

Use runtime logging from the command line

Enabling runtime logging from the command line is the fastest way to use this logging tool. These use npx, which is provided by default as part of npm@5.2.0+. If you have an earlier version of npm, try Runtime logging on Windows or Runtime logging on Mac instructions, or install npx.

  • To enable runtime logging:

      npx office-addin-dev-settings runtime-log --enable
  • To enable runtime logging only for a specific file, use the same command with a filename:

      npx office-addin-dev-settings runtime-log --enable [filename.txt]
  • To disable runtime logging:

      npx office-addin-dev-settings runtime-log --disable
  • To display whether runtime logging is enabled:

      npx office-addin-dev-settings runtime-log
  • To display help within the command line for runtime logging:

      npx office-addin-dev-settings runtime-log --help

Runtime logging on Windows

  1. Make sure that you are running Office 2016 desktop build 16.0.7019 or later.

  2. Add the RuntimeLogging registry key under HKEY_CURRENT_USER\SOFTWARE\Microsoft\Office\16.0\WEF\Developer\.


    If the Developer key (folder) does not already exist under HKEY_CURRENT_USER\SOFTWARE\Microsoft\Office\16.0\WEF\, complete the following steps to create it:

    1. Right-click the WEF key (folder) and select New > Key.
    2. Name the new key Developer.
  3. Set the default value of the RuntimeLogging key to the full path of the file where you want the log to be written. For an example, see


    The directory in which the log file will be written must already exist, and you must have write permissions to it.

The following image shows what the registry should look like. To turn the feature off, remove the RuntimeLogging key from the registry.

Screenshot of the registry editor with a RuntimeLogging registry key

Runtime logging on Mac

  1. Make sure that you are running Office 2016 desktop build 16.27 (19071500) or later.

  2. Open Terminal and set a runtime logging preference by using the defaults command:

     defaults write <bundle id> CEFRuntimeLoggingFile -string <file_name>

    <bundle id> identifies which the host for which to enable runtime logging. <file_name> is the name of the text file to which the log will be written.

    Set <bundle id> to one of the following values to enable runtime logging for the corresponding host:


The following example enables runtime logging for Word and then opens the log file:

defaults write CEFRuntimeLoggingFile -string "runtime_logs.txt"
open ~/library/Containers/


You'll need to restart Office after running the defaults command to enable runtime logging.

To turn off runtime logging, use the defaults delete command:

defaults delete <bundle id> CEFRuntimeLoggingFile

The following example will turn off runtime logging for Word:

defaults delete CEFRuntimeLoggingFile

To troubleshoot issues with your manifest

To use runtime logging to troubleshoot issues loading an add-in:

  1. Sideload your add-in for testing.


    We recommend that you sideload only the add-in that you are testing to minimize the number of messages in the log file.

  2. If nothing happens and you don't see your add-in (and it's not appearing in the add-ins dialog box), open the log file.

  3. Search the log file for your add-in ID, which you define in your manifest. In the log file, this ID is labeled SolutionId.

In the following example, the log file identifies a control that points to a resource file that doesn't exist. For this example, the fix would be to correct the typo in the manifest or to add the missing resource.

Screenshot of a log file with an entry that specifies a Resource ID that is not found

Known issues with runtime logging

You might see messages in the log file that are confusing or that are classified incorrectly. For example:

  • The message Medium Current host not in add-in's host list followed by Unexpected Parsed manifest targeting different host is incorrectly classified as an error.

  • If you see the message Unexpected Add-in is missing required manifest fields DisplayName and it doesn't contain a SolutionId, the error is most likely not related to the add-in you are debugging.

  • Any Monitorable messages are expected errors from a system point of view. Sometimes they indicate an issue with your manifest, such as a misspelled element that was skipped but didn't cause the manifest to fail.

Clear the Office cache

If changes you've made in the manifest, such as file names of ribbon button icons or text of add-in commands, do not seem to take effect, try clearing the Office cache on your computer.

For Windows:

Delete the contents of the folder %LOCALAPPDATA%\Microsoft\Office\16.0\Wef\.

For Mac:

Add-ins are often cached in Office for Mac, for performance reasons. Normally, the cache is cleared by reloading the add-in. If more than one add-in exists in the same document, the process of automatically clearing the cache on reload might not be reliable.

You can clear the cache by using the personality menu of any task pane add-in.

  • Choose the personality menu. Then choose Clear Web Cache.


    You must run macOS version 10.13.6 or later to see the personality menu.

    Screen shot of clear web cache option on personality menu.

You can also clear the cache manually by deleting the contents of the ~/Library/Containers/com.Microsoft.OsfWebHost/Data/ folder.


If that folder doesn't exist, check for the following folders and if found, delete the contents of the folder:

  • ~/Library/Containers/{host}/Data/Library/Caches/ where {host} is the Office host (e.g., Excel)
  • ~/Library/Containers/{host}/Data/Library/Application Support/Microsoft/Office/16.0/Wef/ where {host} is the Office host (e.g., Excel)

For iOS:

Call window.location.reload(true) from JavaScript in the add-in to force a reload. Alternatively, you can reinstall Office.

See also