Power Platform Community Forum Thread Details

I created a “lite” agent in Copilot Chat that reads a user‑uploaded Excel file and generates visuals into a Word document. It can read the file initially, but later in the same conversation it says it no longer has access and asks the user to upload it again.

Why is this happening in Copilot Chat, and how can I prevent it?

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General topics

Hi @FJ-20011125-0

User uploaded files in M365 Copilot Chat are ephemeral by design. They exist only as temporary, single turn context and are not persisted across conversation turns.

Files are temporary attachments, not knowledge sources. When users upload files via the chat UI attachment icon, the file content is available only during the immediate prompt/response cycle. The platform treats them as onetime grounding material, not as persistent agent memory.

You need to treat the file as a persistent knowledge source , not just an in-chat attachment. In Copilot Studio, adding a file as a Knowledge Source means the agent indexes and stores that document (in Dataverse/SharePoint) so it can use it across the conversation (and even future sessions).

Pre-add it as a Knowledge Source in the agent builder (before the conversation). This permanently makes the file’s content part of the agent’s knowledge base.

Hope it helps!