##Install Tor Browser in Ubuntu 16.04 the easy way
Tor Browser (torbrowser-launcher) is available in the default Ubuntu repositories in Ubuntu 16.04 and later. torbrowser-launcher handles downloading the most recent version of Tor Browser Bundle for you, in your language and for your architecture. After installing Tor Browser, it can be launched by searching for tor in the Dash and clicking the Tor Browser icon. The Tor Browser Launcher Settings app is also installed along with Tor Browser.
If you install Tor Browser this way, you will be prompted to update it when an updated version is available.
##Fix Tor Browser in Ubuntu 16.04 without reinstalling it
The reason why Tor stopped working in Ubuntu 16.04 will not be solved by reinstalling Tor, because it is caused by an outdated gpg key. To update the gpg key open the terminal and type:
gpg --homedir "$HOME/.local/share/torbrowser/gnupg_homedir/" --refresh-keys --keyserver pgp.mit.edu
Tor Browser still may not launch after updating the gpg key due to being unable to update the Tor Browser version in:
/home/your-username/.local/share/torbrowser/tbb/x86_64/tor-browser_en-US/Browser/TorBrowser/Docs/sources/versions
Replace your-username with your username and replace en-US with your language in the following commands and run these commands:
cd
mkdir sources
cd sources
touch versions
gedit /home/your-username/.local/share/torbrowser/tbb/x86_64/tor-browser_en-US/Browser/TorBrowser/Docs/sources/versions
A Gedit window will open up. Copy the string TORBROWSER_VERSION=7.5 into the Gedit window and save the file.
Now Tor Browser will launch normally. If an update to Tor Browser is available, the update will be installed as usual.