I am using Ubuntu 16.04. I have tried to download Tor Browser from the Tor website and using the Tor Browser package from the Ubuntu software application. Each time I get a message titled Signature Verification Failed. The message is:

You might be under attack, or there might just be a networking problem. Click Start to try the download again.  

I have tried many times, always getting the same result. I have wiped the hard drive and reloaded Ubuntu three times, and each time I got the same error. I have successfully installed Tor on my laptop which uses the same router and internet connection.

  • Sounds like an issue with torbrowser-launcher, the package that Ubuntu ships that gives errors like you describe. That software isn't maintained by the Tor Project, you might prefer downloading it directly from torproject.org
    – cacahuatl
    Oct 6, 2017 at 23:17
  • Once you download and extract Tor Browser from the Tor Project website, if you could include the terminate output from tor-browser_en-US/Browser/start-tor-browser --debug. If required replace en-US with the appropriate country code for your case.
    – cacahuatl
    Oct 7, 2017 at 4:27

1 Answer 1


This is due to an outdated key. This solution fixed the issue for me:

gpg --homedir "$HOME/.local/share/torbrowser/gnupg_homedir/" --refresh-keys --keyserver pgp.mit.edu

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