Tor: Running multiple instances of firefox

If I run my normal firefox unanonymously, while at the same time running the special instance of firefox in tor bundle (aurora), does this compromise the anonymity in aurora in any way?

Im running the latest version of tor bundle on windows 7.

 

If you care about anonymity enough to use Tor, it's foolish to operate as multiple identities on one machine. It's not just another Firefox instance. It's all information saved by Windows and software running on your machine. You can't be sure that you've secured it all.

Best would be booting TAILS on another machine. If that's unworkable, running TAILS as virtual machine would be better than just running Tor bundle. TAILS will warn you running as guest about leakage to host. But here it's your host, and hopefully not hostile.

 

Yes, that's true.

However I'm not afraid that someone will get access to my computer and look at old history files. What I am interested in is if two instances of firefox can share data which would compromise online anonymity.