An unexpected error occurred on our servers

Support Bug Reports
1

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

GPT wrote a project in ts using a cursor. While writing, it needed to be built, and it tries to build it with the command:

cmd /c npm run smoke

The command returns an error, the entire GUI flashes three times (it executes the command three times), and returns:

Internal Error: An unexpected error occurred on our servers. Please try again, or contact support if the issue persists.

The command itself ends with an error in the project; something isn’t building in the code.

This happens about 10 times, with different models. There’s even a case where the model enters cmd /c npm run build, and everything builds fine. The cursor backend is available; I gave it a huge task, and it completed it immediately.

This isn’t the first time I’ve had this problem interacting with the terminal.

Steps to Reproduce

Make LLM run a command in the terminal

Screenshots / Screen Recordings

package.json - whr_system - Cursor_260209221846.png
package.json - whr_system - Cursor_260209221846.png803×705 25.4 KB

Operating System

Windows 10/11

Version Information

Version: 2.4.31 (user setup)
VSCode Version: 1.105.1
Commit: 3578107fdf149b00059ddad37048220e41681000
Date: 2026-02-08T07:42:24.999Z
Build Type: Stable
Release Track: Default
Electron: 39.2.7
Chromium: 142.0.7444.235
Node.js: 22.21.1
V8: 14.2.231.21-electron.0
OS: Windows_NT x64 10.0.26100

For AI issues: which model did you use?

GPT 5.2 xhigh, GPT 5.3 codex xhigh

For AI issues: add Request ID with privacy disabled

a362155a-5bb4-4fd2-b057-2849c2effc81

Does this stop you from using Cursor

No - Cursor works, but with this issue

3

Hey, thanks for the report. This is a known bug on Windows. When a terminal command returns certain exit codes, Cursor can’t serialize them correctly and crashes with “Internal Error”.

Main thread with updates: Connection Error - Serialize Binary

Try this workaround:

  • Fully close Cursor
  • Open Settings Ctrl+, and search for terminal.integrated.defaultProfile.windows
  • Make sure it’s set to “Command Prompt” (not PowerShell)
  • Restart Cursor

The team is aware of the issue, but there’s no timeline for a fix yet. Your report helps with prioritization.