Copilot Cowork skills not working

For Copilot Cowork skills not being invoked or appearing corrupted, use this end-to-end check:

1. Restart the Cowork session If skills or plugins were just added, removed, or updated, restart the session. Removed plugins are only removed from the next session, and stale plugin versions can remain active until restart.
2. Verify the plugin is installed and enabled In Cowork:
   • Open a conversation or the Cowork home page.
   • Select + > Customize.
   • Confirm the expected plugin is present.
   • Open Sources & Skills and make sure the plugin is toggled on.
   When enabled, plugin skills should appear alongside built-in skills.
3. Reacquire or reinstall the plugin If the install appears corrupted, remove the plugin and add it again from the Microsoft 365 plugin marketplace. After removal, its skills and connectors are removed from the next session, so start a new session after reinstalling.
4. Check whether the plugin is blocked by admin policy If the plugin does not appear at all, it might require organizational approval. Check with the IT admin because some plugins must be approved before they show in the list.
5. Confirm the prompt is specific enough Cowork invokes skills based on the request. Built-in and plugin skills are acquired dynamically as needed during a conversation, so vague prompts might not trigger the intended skill. Use a prompt that clearly names the task or domain the skill supports.
6. If using custom skills, verify the skill files and limits Custom skills are stored in OneDrive under: Documents/Cowork/skills/{name}/SKILL.md Supported limits:
   • Up to 50 custom skills
   • Up to 20 companion files per skill
   • 5 MB per companion file
   • 10 MB total per skill
   Cowork discovers custom skills automatically at the start of each conversation, so after fixing a custom skill, start a new conversation.
7. Check for Information Barriers restrictions If the tenant has Microsoft Purview Information Barriers enabled, plugin or skill management and sharing are not currently supported, and embedded knowledge file uploads are blocked. That can prevent affected plugins or skills from being uploaded or published.
8. If the issue is in Dynamics 365 Sales Copilot scenarios If the failing skill is tied to Dynamics 365 Sales, check these two causes:
   • Republish the Copilot in Dynamics 365 Sales agent if initial publishing failed.
   • In Power Platform admin center > Data policies > Data loss prevention, unblock and group these connectors together in the same policy:
     • Microsoft Dataverse
     • Direct Line channels in Copilot Studio

If the symptom is specifically that skills install but never trigger, the most likely checks are: plugin enabled in Sources & Skills, new session started, plugin approved by admin, and prompt specific enough to invoke the skill.

• Use plugins with Copilot Cowork
• Copilot Cowork common questions
• Application card: Microsoft 365 Copilot Cowork
• Build plugins for Copilot Cowork
• Manage plugins for Copilot Cowork
• FAQ about Copilot in Dynamics 365 Sales
• Use Dynamics 365 Sales skills in Copilot Cowork