If Tun won’t start or kills connectivity, ask whether you need it. Browsers on system proxy often don’t. Games/CLI/AI tools that ignore system proxy benefit more (Tun, Tun & AI).
Symptom → likely cause
| Symptom | Likely cause | Move |
|---|---|---|
| Won’t start | Elevation, service/driver, VPN/TAP, AV | Admin install; clear blockers |
| Starts but offline | Bad nodes, DNS, routing | Check DNS / routing, not more clicks |
| Fresh Win11 | Service → approve → toggle | Read core-comms banner |
Won’t start vs starts but offline
Won’t start: elevation, service/driver missing, other VPN/TAP conflicts, AV. Install service as admin; disable other VPNs; clean leftover adapters.
Starts but offline: bad nodes, DNS, or routing—not a hundred start clicks (DNS, routing).
Suggested order
- Admin install/repair service mode.
- Clear VPN/TAP/AV blockers.
- Confirm traffic on the connections page; verify AI/CLI separately.
- Fall back to system proxy to stay online, then re-add Tun.
Fresh Win11 machines: service → approve → toggle. Communication banners: core communication.
Stop-loss and acceptance
Minimal repro: no other VPN → admin Tun → read the error. Fail closed to system proxy. Done when Tun stays up, target apps tunnel, and disabling Tun returns a working system proxy. Use the download center.