"Unexpected error" after every prompt

Support Bug Reports
22

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

Agents Window fails with:
“An unexpected error occurred”
Local logs show:

  • errorCode: agent_host_bridge_unavailable
  • “Agent host bridge registration wait exhausted before the send left the client”
  • registrationReason / state consistent with bridge never registered in glass window (~70s wait, 9 attempts)
  • runtime reason: managed-local-unavailable
  • layout: glass
    Important:
  • IDE Agent (Open IDE / classic editor Agent chat) works normally
  • Only Agents Window is affected
  • Happens on new chats and resumed chats
  • cursor.general.disableHttp2 is already true
  • %APPDATA%\Cursor\agent-harness folder is missing
  • There is also an old leftover install at C:\Program Files\Cursor (3.5.33) that I cannot delete (no admin). Launching via user install 3.28.5 still reproduces the Agents Window failure.

Steps to Reproduce

  1. Launch Cursor 3.28.5 from:
    C:\Users\abankar\AppData\Local\Programs\cursor\Cursor.exe
  2. Open Agents Window
  3. Open a new chat (or resume an existing one) in a local project
  4. Send “hi” / any message
  5. After ~60–70 seconds: “An unexpected error occurred”

Expected Behavior

Agents Window agent responds like IDE Agent.

Screenshots / Screen Recordings

Screenshot 2026-10-29 093451
Screenshot 2026-10-29 093451918×411 8.82 KB

Operating System

Windows 10/11

Version Information

Cursor 3.28.5
Channel: stable

For AI issues: add Request ID with privacy disabled

Request IDs
Earlier:

  • b9e5a9ce-1fe4-4c7c-aa2f-8f56d9a5fa5a
  • 05c49fe3-f759-48e6-b838-8ab0725699c0
    From today’s sessions:
  • 9ea12cdd-c680-4d64-8824-4777772951b7
  • 69b30e64-67fa-4653-924d-d74098907893
  • a8bca977-8830-4f1c-b2f1-ed46fa42925f
  • a345b6ec-9741-4764-a8f4-5becf9b03230
  • ffb8eb5a-a956-4c5e-be76-47bde9ff0cab
  • cee0292a-a5ba-4716-a99d-bf910cb5bd73

Additional Information

Glass window fails waiting for bridge; IDE window2 later registers Agent Host (example: timeToBridgeRegisterMs: 3189)

  • Selected runtime: connect, reason: managed-local-unavailable
  • Also saw ConnectError / Unable to reach the model provider around Agents Window startup
  • Many MCP servers enabled (Atlassian, Qase, Perforce, Figma, Chrome DevTools, POS DB, etc.) — Extension Host can be slow at startup
  • Workaround: Ctrl+Shift+P → Open IDE (Agent chat works there)

What I already tried

  • Fully quit Cursor + kill leftover Cursor processes + relaunch 3.28.5
  • Waiting before first Agents Window message
  • Using Desktop shortcut to LocalAppData 3.28.5 (not Program Files 3.5.33)
  • HTTP/2 already disabled
  • Cannot uninstall/delete Program Files Cursor (no admin rights)

Does this stop you from using Cursor

Yes - Cursor is unusable