Reprodutible - If an old browser tab remained open from previous session (after re-opening IDE with all tabs restored), the tab shows no content. However, when Cursor agent tries to open new tab, IDE crashes instantly.
Steps to Reproduce
Make Cursor agent open a new browser tab
Close IDE
Restart IDE so that it restores all tabs, including previous browser tab session
Expected Behavior
No crashes. Old tab is either automatically closed (if unused), or reused.
Thanks for the report. You’re running a couple versions behind now (v3.17, compared the to the current stable v3.20). Can you please upgrade and let us know if you’re still facing an issue?
Didn’t try latest version yet, but it happened again:
The last completed step was locking the browser on http://localhost:5180/knowledge-base/pl/signup/pilot after a successful snapshot of that page (two question fields were already visible). I then fetched the fill/click tool schemas. I had not filled anything, clicked anything, or opened another route yet.
What is “locking browser” precisely? Navigating to page, or something else?
Locking is not navigation. It is a Cursor browser-tab mutex.
Navigation had already finished: the tab was on http://localhost:5180/knowledge-base/pl/signup/pilot. browser_lock then marked that tab as agent-controlled so you would not click around while I filled/clicked. Unlock is the reverse, when the agent is done.
You can still take the tab back with “Take Control.”
Hey @DjWarmonger, thanks for confirming it still happens on the new version. I can see the three restarts on our side yesterday afternoon, including the one right after you updated.
I haven’t been able to repro the crash yet.
When it goes down, does the whole Cursor app disappear, or do you get a dialog saying the window terminated unexpectedly with a Reopen button?
Right after Cursor comes back up, run Ctrl+Shift+P → “Developer: Capture and Send Debugging Data”, keep the default options and press Enter. That sends us the logs from the session that went down. Just let me know here once you’ve run it.
Until we have a fix, closing the Browser tab before you quit Cursor (or closing the restored empty one before asking the agent to use the browser) should keep it from happening, since the agent reuses that old tab instead of opening a fresh one.
