MCP server processes are not terminated and accumulate over time, causing memory leaks

[f1nder (Oleksandr Moroz)]

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

Cursor IDE continuously spawns new MCP server processes but does not properly terminate old ones. As a result, the number of running MCP processes grows indefinitely, consuming system memory and eventually degrading system performance.

Steps to Reproduce

1.	Open Cursor IDE.
2.	Work with any project that triggers MCP server usage 
3.	Observe system processes while interacting with MCP-backed features (e.g., via ps aux, Activity Monitor, or System Monitor).
4.	Cursor repeatedly spawns new MCP server child processes.
5.	Old/however no-longer-used MCP processes are not terminated.

Screenshots / Screen Recordings

Operating System

MacOS

Current Cursor Version (Menu → About Cursor → Copy)

Version: 2.0.77
VSCode Version: 1.99.3
Commit: ba90f2f88e4911312761abab9492c42442117cf0
Date: 2025-11-13T23:10:43.113Z (5 days ago)
Electron: 37.7.0
Chromium: 138.0.7204.251
Node.js: 22.20.0
V8: 13.8.258.32-electron.0
OS: Darwin arm64 25.1.0

Does this stop you from using Cursor

Yes - Cursor is unusable

[f1nder (Oleksandr Moroz)]

[deanrie]

Hey, thanks for the report! This is a confirmed bug affecting MCP server process lifecycle management starting from Cursor 2.0.34. Several users on Windows and macOS have reported similar issues.

The root cause is a race condition where Cursor starts multiple MCP client instances without properly terminating the old ones.

To help prioritize a fix, could you please share:

• Which MCP server(s) you’re using (from ~/.cursor/mcp.json)
• Logs from your MCP server
• Whether this happens on every Cursor restart or only during active use

I’ll mark this as related to the existing ticket.