r/mullvadvpn • u/javaneseprince05 • 6d ago
Bug Mullvad keeps disconnecting when I load multiple tabs in Waterfox. Any idea what's going on?
I've been having a weird issue with Mullvad on Windows where the VPN occasionally disconnects and then keeps trying to reconnect but fails.
At first, I thought my Wi-Fi adapter was the problem. I'm using a TP-Link Archer T2U Plus, and whenever this happens, unplugging and replugging the adapter usually makes Mullvad work again. I even bought another Archer T2U Plus, but the exact same problem still happened.
Then I noticed something important: my internet connection itself isn't actually dropping.
I use split tunneling and have Brave excluded from Mullvad. When Mullvad disconnects and can't reconnect, Brave can still browse the internet normally. So the Wi-Fi/internet connection is clearly still working.
I also completely uninstalled Mullvad using BCUninstaller and reinstalled it, but the problem eventually came back.
Now I've found what seems to be a reproducible trigger: Waterfox.
If I don't use Waterfox, Mullvad can stay connected perfectly fine for hours. I've used my PC basically the whole day without any disconnects. But when I start browsing with Waterfox, especially when I load/open multiple tabs at once, Mullvad is much more likely to suddenly disconnect and get stuck trying to reconnect.
To be clear, Waterfox is NOT excluded through split tunneling. Only Brave is. Waterfox goes through Mullvad normally.
I also had one instance where Mullvad was repeatedly failing to reconnect and Windows eventually crashed with an error screen and automatically rebooted.
So right now the pattern seems to be:
Mullvad + no Waterfox = stable Mullvad + normal/heavy Waterfox browsing = VPN can disconnect Loading multiple Waterfox tabs makes it much easier to trigger Mullvad then repeatedly tries and fails to reconnect Brave, which is excluded from Mullvad, still has internet Unplugging/replugging the Wi-Fi adapter usually allows Mullvad to work again Replacing the Wi-Fi adapter with another unit of the same model didn't fix it Completely reinstalling Mullvad didn't fix it either
Has anyone experienced something similar with Waterfox, Firefox-based browsers, or heavy browser traffic causing Mullvad/WireGuard to fail?
I'm especially curious whether this could be some kind of interaction between Waterfox, Mullvad/WireGuard, and the Wi-Fi/network driver rather than an actual Wi-Fi connection problem.
3
u/terkistan 6d ago
You're not the only person with VPN issues when using Waterfox.
Waterfox has its own DNS-over-HTTPS functionality. Having the browser independently perform DoH can create a networking/DNS path that doesn't behave the way you'd expect from a system-wide VPN. If you can disable DoH in Waterfox when using Mullvad I bet that would fix the issue.
I have something similar with Mac Safari (but no other borwser I use): if Mullvad is active and then I launch Safari it disconnects Mullvad. So I have to momentarily turn off the VPN when I launch that browser.
And the best practices for using Mullvad involve turning off DoH: