Cursor using 105GB memory causing "Out of application memory" on macOS Tahoe 26

Bug Reports
1

Where does the bug appear (feature/product)?

Somewhere else…

Describe the Bug

My setup:

  • MacBook Pro 16-inch, Nov 2024
  • Chip: Apple M4 Max
  • Memory: 64GB
  • Startup disk: Macintosh HD (1.6TB of 2TB available).
  • macOS: Tahoe 26.0.1

When Cursor is left open overnight with large workspace loaded (8-10 projects) and no agent tasks running, Cursor memory usage increases to >100GB over night.

Steps to Reproduce

  1. Start MacBook
    a. External Display as main display. I use a 49" widescreen LG+ Ultra monitor.
    b. Wifi connection to Internet (1Gbit fiber)
    c. (Optional) Ethernet connection on different subnet connected to Internet (1Gbit fibber)
  2. Open Cursor
  3. Open .code-workspace file containing 13 folders. 11 are .NET projects with git repos. 1 is local data for the overall project (with git repo) and 1 is the folder containing the .code-workspace file.
  4. Leave the system overnight so that it turns off the display.
  5. Return the next morning to find either
    a. The system has restarted due to a “critical error”.
    b. The system is “Out of Application Memory” with Cursor consuming >100GB. (No, that’s not a type. 100 GIGABYTES of RAM).

Expected Behavior

Ummm… maybe Cursor shouldn’t crash the whole machine?

Operating System

MacOS

Current Cursor Version (Menu → About Cursor → Copy)

Version: 2.0.43 (Universal)
VSCode Version: 1.99.3
Commit: 8e4da76ad196925accaa169efcae28c45454cce0
Date: 2025-10-30T18:49:27.589Z
Electron: 34.5.8
Chromium: 132.0.6834.210
Node.js: 20.19.1
V8: 13.2.152.41-electron.0
OS: Darwin arm64 25.0.0

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Additional Information

This first happened several weeks ago (pre Cursor 2.0) and has grown more frequent. It has happened 3-4 times in the last week.

Does this stop you from using Cursor

No - Cursor works, but with this issue

2

UPDATE: I’ve been leaving Cursor open over night the last few days to see if this is reproducible. Well, it’s regular as clockwork. It seems this is triggered by macOS going into “sleep” mode. Cursor is causing WindowManager to fault and reboot the entire machine.

I suppose I’ll have to make it a habit to ALWAYS shut down Cursor before I knock off for the day. Trouble is, sometimes, I don’t recognize when I walk away from my desk that I won’t be back…

Is there anyone here from the Cursor support team who can at least acknowledge that they’ve seen and are aware of this bug?

3

UPDATE: At the end of the day, yesterday, I went to eat with the full intentions to return to my desk. However, after the meal, I just didn’t have it in me. This was around 6pm. At 10pm, I returned to my desktop to shut down Cursor to avoid the nightly reboot.

Too late.

My MacBook had already gone into “sleep” mode and, when I woke it up, :double_exclamation_mark::collision:BOOM :collision::double_exclamation_mark: – the Window Server crashed and rebooted the machine.

So, I let everything just restart on it’s own and retired for the night.

However, the post-crash restart re-opened all the app that were around when the crash happened… including Cursor.

So, this morning, I greeted with another reboot when I wake up my MacBook.

Long story short, this DOES NOT HAPPEN unless Cursor is open on the desktop. It does not matter whether Cursor is “empty” (i.e., no files, folders, projects, or workspaces open) or not. If Cursor is open when the MacBook goes to sleep, it crashes the Window Server and restarts macOS.

Like clock-work…

Every.

Single.

Time.

Why? I can’t say. :man_shrugging:

Cursor has several extensions installed, including Claude Code and Codex. Maybe these are the culprits or, at least, co-conspirators? However, Cursor started doing this several weeks ago before either of those were installed.