URGENT — Cursor latest version is destroying files and running commands (data loss) — lost full project using composer model + claude sounset4.5 — anyone else?

[erraoudy (Said)]

Since upgrading to the latest Cursor release, I experienced severe data loss: Cursor ran some commands while I asked it to update a file, and large parts of my project were removed. After that, if I request an update to a file, Cursor sometimes replaces the file content with an empty file (or deletes it entirely). This happened while using Composer-model workflows and Claude (sonnet/4.5) models. I’ve lost a full project and several commits. This is urgent and reproducible for me.

Version: 2.0.60
VSCode Version: 1.99.3
Commit: c6d93c13f57509f77eb65783b28e75a857b74c00
Date: 2025-11-05T00:50:54.645Z
Electron: 37.7.0
Chromium: 138.0.7204.251
Node.js: 22.20.0
V8: 13.8.258.32-electron.0
OS: Darwin arm64 24.6.0

[Sirius7Cangshu]

The main reason for this is Claude Sonnet 4.5. The cause is that when Claude solves a problem and needs to choose a solution, it cannot make an accurate choice, which leads to a ‘swinging left and right’ situation, and then a large-scale deletion of the source code.