Hey there! Thanks for the report - absolute Windows paths with backslashes in chat links fail to open (\ turns into %5C). This is something we’ve seen before, and it’s an issue we’re tracking. Merging into Unable to open file linked in chat.
Workaround: copy the path text and open with Ctrl+P / Ctrl+O, or ask the agent to wrap the path in backticks. The file-edit header also still works. I’ll post updates on the primary thread.