If SmartScreen blocks KuaiLian VPN on Windows, confirm the installer from the current download page, check Digital Signatures in file properties, allow a one-time test run if trusted, then restore Defender rules and check old VPN virtual adapters.
SmartScreen flashes blue and many search how to disable Defender. Safer: Properties → Digital Signatures on the installer. Valid signature but still blocked may mean corporate policy; no signature—stop.
Post-install connect issues → Windows guide. Corporate VPN blocks → corporate network article.
Block type routing
- Unknown publisher: More info → Run once if source trusted; abort if unknown mirror.
- Defender threat: Don't blanket exclude; re-fetch from download page; note threat name.
- Admin required: Run as administrator; on locked corporate PCs, ask IT.
- Missing virtual adapter: Device Manager TAP/TUN; remove old VPN stacks first.
Temporary allow vs permanent AV off
One-time firewall allow for testing is fine; permanently disabling Defender widens unrelated risk. Hotspot + personal device helps separate policy blocks from bad installers.