Cursor Update Broke Claude Code Plugin? 2026 Quick Fix Guide (Windows/macOS/Linux)

February 26, 2026

If Cursor just updated and your Claude Code plugin is suddenly broken, this is the fastest recovery flow.

Common symptoms:

Plugin button does nothing
Sidebar entry disappears
Plugin tab fails to open
UI opens but requests spin forever

First: classify the failure

A) UI failure

Likely extension state corruption, stale cache, or incomplete reload after update.

B) Runtime failure

Likely CLI path issue, permission mismatch, or proxy/network conflict.

5-minute recovery sequence

1) Reload extension + window

Disable Claude Code plugin in Cursor
Close Cursor
Re-open and re-enable plugin
Run Developer: Reload Window

2) Clear extension state cache (safe)

Keep project code intact
Clear extension-level state/cache
Restart Cursor

3) Verify Claude CLI availability

claude --version
which claude

If claude is missing, fix installation/path first.

4) Isolate proxy/network side effects

If you use proxychains/system proxy:

Test once without proxy
Re-enable proxy and compare behavior

5) Reinstall plugin (last quick step)

Uninstall plugin
Restart Cursor
Install again

Failure branch tree

Case 1: Button/entry missing

Check auto-disabled extension → reload UI → reinstall plugin.

Case 2: Opens but connection errors

Check CLI path → terminal permissions → proxy/network chain.

Case 3: Broken in one repo only

Check repo-level scripts/hooks/rules for conflicts.

When rollback is the best move

Rollback quickly if:

Multiple projects broke right after update
Community reports cluster on the same Cursor version
You completed all 5 steps and still fail

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