Cursor not working? Fixes for startup, AI and sign-in errors

When Cursor is not working, the cause is usually one of five things: a bad install or startup, a network or proxy that blocks HTTP/2, an extension that conflicts with its AI features, a blocked sign-in domain, or a slow editor weighed down by old chats and extensions. Cursor's help center covers each of them, and its status page showed "All Systems Operational" when we checked on October 30, 2026, so the problem is probably on your side. This guide collects the fixes from Cursor's troubleshooting help, in the order that is fastest to try.

We read the pages and did not run the steps ourselves. Menu names and defaults are as of October 30, 2026.

Check the Cursor status page first

Open status.cursor.com. It now redirects to status.x.ai, where Cursor's status is published. On October 30 its status feed reported all systems operational. If it shows an incident, wait for it to clear before changing anything on your machine.

Cursor opens to a blank screen or won't start

Cursor's install help lists these fixes for a blank screen:

1. Quit and restart Cursor.
2. On Mac, drag Cursor to the Trash and reinstall from cursor.com/download.
3. On Windows, run Cursor as administrator.
4. Fully quit Cursor, then reopen it. Use Cmd+Q on Mac, or exit from the tray on Windows and Linux.

If macOS says "Cursor is damaged", Cursor says this is a macOS issue and not a corrupted download. Quit Cursor, force-quit leftover processes in Activity Monitor, wait a minute and reopen it. If the warning stays, trash the app, empty the Trash and download it again. If it still appears, restart the Mac.

To rule out an old build, press Cmd/Ctrl+Shift+P, run "Cursor: Attempt Update" and restart when prompted.

AI features, Agent or Tab stop working

Start with the built-in test. Go to Cursor Settings, then Network, and click Run Diagnostics. It checks your connection to Cursor's servers and flags what affects AI features or updates.

Switch to HTTP/1.1

Cursor streams AI responses over HTTP/2, and some corporate proxies, Zscaler among them, block it. Set Cursor Settings, Network, HTTP Compatibility Mode to HTTP/1.1, then restart Cursor. The help center gives the same fix when Tab suggestions don't appear.

Allow Cursor's domains through a firewall

Cursor's network page asks you to allowlist *.cursor.sh, *.cursor-cdn.com, *.cursorapi.com, cursor.com and *.cursor.com. The Grok Bot hosted computer also needs *.cursorvm.com and *.*.cursorvm.com.

Cloud Agents stuck on "Loading..."

If cursor.com/agents hangs but the desktop app works, Cursor says a secure web gateway such as Cloudflare WARP, Zscaler or Netskope may be scanning responses as downloads. Turn the gateway client off, or try from another network. If the page then loads, ask IT to exclude cursor.com and *.cursor.com from TLS inspection and file scanning.

VPN, SSH and "suspicious activity"

• After a VPN disconnects: Cursor can inherit the VPN's DNS settings, which causes DNS errors. Fully restart Cursor, not just reload the window. If it persists, check your system DNS: run scutil --dns on macOS, or read /etc/resolv.conf on Linux.
• Over Remote SSH: AI runs on your local machine, so check your local connection first, then the remote host's memory and CPU. Add ServerAliveInterval 60 and ServerAliveCountMax 3 to your SSH config for the host, and restart Cursor after reconnecting.
• "Suspicious activity" message: Cursor says a security measure blocked the request, and VPNs can trigger it. Turn off the VPN, start a new chat and retry after a few minutes, or sign in with Google or GitHub.

Sign-in fails

Cursor's sign-in domains page says sign-in is moving to accounts.spacex.ai and accounts.x.ai. If those hosts are blocked, sign-in falls back to the old page, and Cursor says that fallback was scheduled to end on October 30. After that, networks need to allow the new hosts. Existing sessions stay signed in.

Cursor lists these as the preferred wildcards: *.spacex.ai, *.x.ai, *.grok.com, *.grokusercontent.com and *.grokipedia.com. If wildcards aren't allowed, the minimum hosts are accounts.x.ai, accounts.spacex.ai, auth.x.ai, auth.grok.com, auth.grokusercontent.com and auth.grokipedia.com. The *.cursor.sh and other Cursor domains above are still required.

An extension is interfering

Extensions that add their own AI completions or capture keyboard shortcuts can conflict with Tab and Cursor's shortcuts. Other AI coding assistants are the most common source, according to the help center.

1. Run "Disable All Installed Extensions" from the command palette.
2. Check whether the problem is gone.
3. Re-enable extensions one at a time until it returns.

You can also launch with cursor --disable-extensions from a terminal to test with none active.

Cursor is slow or uses too much memory

For high CPU or memory, and for input delay, Cursor points to extensions first. Disable the ones you don't need, then test with cursor --disable-extensions. Add large generated folders such as dist/, build/ and .next/ to .cursorignore. Run "Show Running Extensions" to see each extension's CPU and memory use.

Cursor says old Agent conversations are usually the largest use of disk, not extensions. Press Cmd/Ctrl+Shift+P and run "Delete Old Chats...", pick a retention window such as 30 days, then run "GC Agent KV Blobs" to shrink the database file. Running only the first command leaves the file the same size. Worktrees in ~/.cursor/worktrees/ are cleaned up automatically, with defaults of 25 worktrees and 50 GB.

Agent ignores your files or fails to start

• Agent can't see a file: A .cursorignore in the project root blocks files from Agent, codebase search and @ mentions, and .gitignore patterns can also hide files. Check both, run "Reindex", or attach the file with @ and its name.
• "Agent Execution Timed Out": The extension host didn't start within 60 seconds. Antivirus or endpoint security software on managed machines is a possible cause. Run "Developer: Export Logs...", select Main, Window and Extension Host, and send the zip with your OS and Cursor version to support.
• Commands behave differently: Cursor sets CI=1 in terminal commands for cleaner output. Run unset CI && your-command-here if a project reacts to it.
• Undo Agent changes: Hover over an earlier message and click Restore Checkpoint. Checkpoints are local and separate from git.

Tab suggestions don't appear

Cursor lists four causes: a plan limit (Free and legacy Hobby plans have a limited Tab allowance that pauses until it resets), HTTP/2 blocked on your network, an outdated version, or no internet connection. For poor suggestions in a new or empty file, make a few manual edits first so Tab has context. You can turn Tab off for file types such as markdown or JSON from the Tab indicator at the bottom right.

If nothing works

Post on forum.cursor.com with your Cursor version (Cursor, About Cursor), your OS, the steps to reproduce and a request ID. To get the ID, open the chat's "..." menu and choose Copy Request ID. Console errors are under Help, Toggle Developer Tools. With Privacy Mode on, support can see less, so Cursor suggests temporarily turning on Share Data for unexpected agent behavior if you are comfortable with that.