Copilot Migration : Unable to Load Conversation Content

Hello,

I am seeking assistance with a specific Copilot conversation that became inaccessible following the Copilot update/migration that occurred on approximately 5 October at 11:00 PM (UK time).

I have already contacted Microsoft Support and received a support reference for the issue. I was then directed to raise the matter within the Community Hub.

The issue persists across multiple devices despite subsequent updates to both the browser (laptop) and Copilot application (mobile phone). Other conversations became accessible again after the updates, however one conversation remains inaccessible.

Conversation Details

• Approximate size: ~4,000 messages
• Type: Long-running creative writing and worldbuilding project
• Duration: Approximately 12 months

Summary of Issue

• The conversation was active and functioning normally, with the last known activity on 28 September.
• Following the Copilot update/migration on 5 October, conversations became temporarily inaccessible.
• After browser/application updates and interface refreshes on 7 October, my other conversations became accessible again.
• One conversation remains inaccessible on both desktop and mobile devices.

Current Behaviour

• The conversation is still visible in my chat history and remains pinned.
• The conversation title and recent activity date are still displayed.
• Opening the conversation shows a loading indicator followed by:

                     "Unable to load content - try refreshing"

• Selecting Refresh causes the Copilot page to become blank and non-interactive.

Additional Observations

• I attempted to move the conversation into a Notebook for preservation.
• The conversation briefly appeared there with an incorrect date of January 1970, then disappeared from the Notebook while remaining visible in chat history.
• Browser developer tools report: ERR_HTTP2_PROTOCOL_ERROR
• The conversation URL still exists and has been preserved.
• I have preserved screenshots, timeline information and error messages which I can provide if required.

Question

Has anyone else experienced a similar issue with a single long-running conversation following the October migration, and if so, were you able to restore access?

Any guidance would be appreciated.

Thank you.