File upload limit with my CoPilot Agent, how to reset?

There is no documented Copilot Studio control to purge /app/uploads/ or configure its retention; determine which agent harness is in use, then apply the supported lifecycle below or open a Microsoft support case if the unexplained 20-file count remains blocked.

If the agent uses the GitHub Copilot harness

Conversation attachments are retained for 28 days after the last activity in that conversation and are then deleted automatically. The documented retention period is not presented as configurable, and no immediate purge operation is documented.^1^

Therefore:

1. Stop sending messages to the affected conversation; further activity restarts its inactivity period.
2. Use a genuinely separate conversation for new uploads.
3. If a new conversation still inherits the same 20-file count, treat that as a service-side or agent-state issue rather than expected conversation retention.
4. Open a Microsoft support request through the Power Platform admin center and provide:
   • Environment ID and agent ID—do not post them publicly.
   • Whether the agent uses the GitHub Copilot harness or standard harness.
   • Channel where this occurs: Preview, Microsoft Copilot, Teams, or web chat.
   • Exact limit message and timestamp.
   • Evidence that a newly created conversation inherits the count.
   • A note that the agent can list /app/uploads/ but has read-only access.
   • A request to clear or investigate the agent’s server-side attachment/sandbox state.

The published GitHub-harness limits specify 16 MiB per attachment and 28-day conversation retention, but not a 20-file lifetime cap.^1^

If the agent uses the standard harness

For files accumulated in the current conversation context, add a cleanup point to the topic:

1. Open the agent in Copilot Studio.
2. Open the topic that processes the uploaded file.
3. After the file-analysis steps, add a Clear variable values node.
4. Select the option to clear conversation history for the current session.
5. Save, test, and publish the agent.

Microsoft specifically recommends this pattern after each processed file when an agent regularly handles several files. It releases accumulated file content so later uploads do not exceed the model’s limit.^2^

This clears conversation context; it is not a documented filesystem deletion API. Since starting a new conversation already did not help in this case, use this only if testing confirms the count is conversation-history based.

Check whether these are knowledge-source files

Maker-uploaded knowledge files are different from end-user conversation attachments. They are stored in Dataverse, create separate copies even when names match, and can be deleted manually:

1. Open the agent.
2. Select Knowledge.
3. Find the uploaded file.
4. Select … → Delete → Delete.

Deletion is permanent.^3^

Deleting the original OneDrive file is not this operation. If the files do not appear on the agent’s Knowledge page, do not delete unrelated knowledge sources—they are probably conversation attachments instead.

Why the 20-file behavior needs escalation

Current standard-harness documentation lists 500 uploaded files and 500 knowledge sources per agent, not a 20-file agent-wide limit.^4^ Microsoft also does not document /app/uploads/ as a maker-managed storage location or expose a retention policy for that path.

Consequently, do not attempt to modify or delete that directory through custom tools. For a daily upload-and-analyze workflow, the supported design is:

• Clear conversation history after each processed file on the standard harness.
• Keep transient files as conversation attachments rather than knowledge sources.
• Delete maker-uploaded knowledge files from Knowledge when they are no longer required.
• Escalate an inherited 20-file sandbox count for service-side cleanup.

References

1. Attach files to a conversation (GitHub Copilot)
2. Allow file input from users - Microsoft Copilot Studio
3. Use uploaded files with generative answers nodes - Microsoft Copilot Studio
4. Quotas and limits - Microsoft Copilot Studio | Microsoft Learn