Very big - bug!

[Neculai_I_Fantanaru]

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

Look what the problem is. I’ve been working on a php project for a few days. On this project I worked with several AI Agents in parallel (Auto, Composer and Claude.AI (Opus 4.5).

Well, the last chat with the latest changes in the files was done with Agent (auto).

Now comes the problem. Today I opened Cursor. It opened with the chat from Claude.AI. But as soon as this chat was opened, 8 php files were instantly modified. So, Cursor automatically modified the files WITHOUT me asking him anything, without me writing him any message.

Now, the chat with ClaudeAI was a few days old, in the meantime I had pushed the same files with Agent (Auto), in another chat.

So, imagine that instantly Cursor modified the files in the old version that I had been working on with Opus 4.5 and thus 3-4 days of work were reset, because I have to start over.

Luckily I made a backup yesterday

But, as an idea, how is it possible for Cursor (with the Opus 4.5 agent or another agent) to make changes to files right when Cursor opens, without me asking it to do so?

The mistake is with Cursor, probably it has set somewhere the option to keep intact the last version of the files that were worked on in that chat. But it is a big mistake, because if I make other changes to the files, alone or with another agent, then it will always reset that file to their old update in that chat.

Steps to Reproduce

Cursor should not make any changes to the files when I open the IDE.
Cursor should not make any automatic changes to the files, without me asking it to do so.

Operating System

Windows 10/11

Current Cursor Version (Menu → About Cursor → Copy)

Cursor Version 2.1.3.9

For AI issues: which model did you use?

Opus 4.5

For AI issues: add Request ID with privacy disabled

a138a26b-e918-4e27-8d34-b56b422e3cab

Does this stop you from using Cursor

No - Cursor works, but with this issue

[deanrie]

Hey, thanks for the detailed report - this matches a known issue with auto-modifications on IDE startup (discussion and ticket already exist):

• Thread: Cursor modifying files on startup
• Similar cases: The cursor adds blank lines

We need your help to clarify, it’s important:

1. Can you attach a git diff of the affected PHP files: is it just spaces/blank lines or an actual rollback to old code?
2. Were there any “unaccepted” changes from the Agent in these files (did you see a banner with Review/Keep/Undo)?
3. Check if it reproduces when starting with extensions disabled: cursor --disable-extensions
4. Run git config core.autocrlf and share the value.

Temporary steps that have helped others:

• Open each affected file and click Keep/Undo in the top banner (or “Accept all changes” in Review) for all files with pending changes.
• Then restart Cursor and check if the auto-modifications disappear.

Let me know if the workaround helps - it will speed up the fix.

[Neculai_I_Fantanaru]

Write me private message.

I can send you the original files, and the ones that are automatically modified by Opus 4.5 when I open Cursor.

–-This is the message I received as soon as I selected the chat with Opus 4.5. It can be seen that it made changes instantly, as soon as I opened the chat.–

Excelent! 🎉

Să recapitulez ce am implementat:

Auto-expirare bazată pe ultimul Enter:

Fereastra cu informații (cititor/carte) dispare automat după 60 secunde de la ultima scanare

Funcționează corect chiar dacă navighezi pe alte pagini între timp

Timer-ul se resetează la fiecare nouă scanare (Enter)

Dacă mai ai nevoie de altceva, spune-mi! 👍

Here are my chat settings:

[Neculai_I_Fantanaru]

But I discover something nice. I press “Undo All”, and all the files were modified again (but I didn’t check how they were verified).

Then I closed that chat and opened it again. This time, nothing was modified in the files, they remained intact.

So, I would say that it updated those files because the Chat is set to finish the job

[Neculai_I_Fantanaru]

I figured out what the problem was!

First, I compared the modified files by Opus 4.5 with the original ones. And I noticed that there was absolutely no difference.

But then I noticed something interesting. It seems that Opus 4.5 has modified ALSO these 2 files, but they don’t exist in my folder. I don’t know where it modified these two files.

Question: what are these two files, which don’t exist in my folder, but nevertheless, they change a lot of things in my php application (website).