Can I use Tor with a browser besides Tor Browser?

Using Tor in another browser can leave you vulnerable without the privacy protections of Tor Browser.

Using Tor in another browser is unsafe because those browsers are not designed with Tor's privacy protections in mind.
Even if you manage to connect them through the Tor network, they can still reveal identifying information such as:

• Your real IP address, through DNS leaks or WebRTC.
• Your operating system details, fonts, and plugins, which can be used for fingerprinting.
• Tracking cookies and cache that remain after browsing sessions.

Tor Browser is carefully developed and modified to prevent these kinds of leaks and to make Tor users look alike, which greatly improves anonymity. Other browsers lack these defenses, so using them with Tor can make you easier to identify and track.

Is it safe to run Tor Browser and another browser at the same time?

If you run Tor Browser and another browser at the same time, it won't affect Tor's performance or privacy properties. However, be aware that when using Tor and another browser at the same time, your Tor activity could be linked to your non-Tor (real) IP from the other browser, simply by moving your mouse from one browser into the other.

Or you may simply forget and accidentally use that non-private browser to do something that you intended to do in Tor Browser instead.