"Sorry, this conversation has reached its limit. Let's start a new chat."

I am experiencing what appears to be a more advanced version of this issue and would welcome any guidance from Microsoft or other users.

I have a long-running Copilot conversation containing many months of accumulated context, chronology, analysis and working material. The conversation remains fully accessible, searchable and readable, and the contents have also been preserved within a Notebook.

However, neither the original conversation nor the Notebook can be continued. This suddenly started in early October 26 but was fine till then.Any attempt to submit a new prompt results in messages such as:

"Thanks for this conversation! I've reached my limit, will you hit 'New topic,' please?"

or similar messages directing me to start a new topic.

The behaviour is identical in Microsoft Edge and the Copilot app on Windows 11.

My concern is not loss of data. The conversation and Notebook still exist. My concern is the loss of continuity and functionality within a conversation containing many months of accumulated context.

Can Microsoft or other users confirm:

1. Whether this behaviour is consistent with a hard Copilot conversation limit.
2. Whether such conversations can ever be restored to an active state.
3. Whether there is a Microsoft-supported method of migrating the accumulated context into a new working conversation.

Any guidance would be greatly appreciated.