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

> Cursor's own help center covers blank screens, blocked HTTP/2, extension conflicts, sign-in domains and slow editors. Here are the fixes in the order to try them.

URL: https://claudegpt.si/news/cursor-not-working-fixes  
Published: 2026-10-30T18:51:00.814Z  
Author: ClaudeGPT Si Newsroom  
Section: Guides  
Topics: Cursor, Troubleshooting, AI coding  
Publisher: ClaudeGPT Si

## Key takeaways

- Cursor's status feed reported all systems operational on October 30, 2026, so most problems come from the install, network or extensions.
- Setting HTTP Compatibility Mode to HTTP/1.1 fixes AI features behind proxies that block HTTP/2.
- Sign-in is moving to accounts.x.ai and accounts.spacex.ai, and networks that block them need an allowlist update.

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](https://cursor.com/help/troubleshooting/install-issues), 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](https://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.

## Frequently asked questions

### Why is Cursor not working?

Check the status page first. If it is clear, the usual causes in Cursor's help center are a blocked network, a conflicting extension, an outdated version or a blocked sign-in domain.

### How do I fix Cursor AI not working behind a proxy?

Go to Cursor Settings, Network, set HTTP Compatibility Mode to HTTP/1.1 and restart Cursor. Cursor says some proxies, such as Zscaler, block the HTTP/2 it uses for streaming.

### How do I find which extension breaks Cursor?

Run Disable All Installed Extensions from the command palette, then re-enable extensions one at a time until the problem returns. Cursor also supports launching with cursor --disable-extensions.

### How do I report a Cursor bug?

Post on forum.cursor.com with your Cursor version, OS, reproduction steps and a request ID from the chat's menu, using Copy Request ID.

## Sources

- [Installation and startup](https://cursor.com/help/troubleshooting/install-issues), Cursor
- [Network, proxy, and remote connections](https://cursor.com/help/troubleshooting/network), Cursor
- [Which domains does Cursor sign-in need?](https://cursor.com/help/troubleshooting/sign-in-domains), Cursor
- [Agent troubleshooting](https://cursor.com/help/troubleshooting/agent-issues), Cursor
- [Extension conflicts](https://cursor.com/help/troubleshooting/extensions), Cursor
- [Performance](https://cursor.com/help/troubleshooting/performance), Cursor
- [Tab completions troubleshooting](https://cursor.com/help/troubleshooting/tab-issues), Cursor
- [Reporting a bug](https://cursor.com/help/troubleshooting/reporting-bugs), Cursor
- [Cursor status](https://status.cursor.com), Cursor