HowTo: Install Tor on Virtual box

1) boot from DVD/USB and set a password, then open a terminal
  a) sudo gedit /usr/lib/python2.7/dist-packages/tails_installer/creator.py
     -> search for "Only pay attention to USB and SDIO devices"
     -> comment out next 7 lines (until and including "continue") by prepending a "#" (a changing font color means you did it right)
  b) sudo /usr/bin/python -tt /usr/lib/tails_installer/tails-installer -u -n --clone -P -m -x
     -> choose your hdd and create the Tails device
  c) mount "Tails" partition from just created device/drive using Applications | Utilities | Disks
  d) gedit /media/amnesia/Tails/syslinux/live*.cfg
     (3 files open in gedit)
     -> delete every occurence of "live-media=removable " in these files

2) reboot from disk (hdd) and set a password, then open a terminal
  a) sudo gedit /usr/share/perl5/Tails/Persistence/Setup.pm
     -> find "foreach my $check (@checks) {"
        -> AFTER insert new line: "=begin" (important: this MUST be placed in column 1! (a changing font color means you did it right))
     -> find (32 lines below) "return 1;"
        -> 2 lines BEFORE (above the "}" that is in the same column as the first "r" of "return 1;")
       insert new line "=cut"  (important: this MUST be placed in column 1!)
  b) run "Configure persistant volume" as you normally would from Applications | Tails

Finished.

You might want to save the two files (at least /usr/share/perl5/Tails/Persistence/Setup.pm) and replace them after each reboot by a script (take care of ownership and permissions!) so that your hdd-Tails behaves exactly like a USB-Tails

Reference: https://www.reddit.com/r/tailswiki/wiki/index/internal-hd-install