Is the Lenovo Thinkpad T420 compatible with Linux Mint?
 

Looking into buying a one, and I wanted to check if it's compatible before I do so.

I won't say any guarantees as I don't have one,and I don't run mint, however Thinkpads have a history of working EXTREMELY well with linux, so I'd be willing to bet it will be.

I have a T420s, T420, and T440 that all run OpenSUSE without issue. I've never tried Mint on them, but I'd be surprised if it had any issues. All of mine have the Intel wifi and standard integrated graphics though, I don't know how the optional add-on graphics adapter would behave.

Ok, I'll wait until the one I ordered arrives, then post to confirm if it is compatible. That way we can wrap up this with a definite answer.

I hope you ordered the one with Intel graphics and not with Optimus! If not, look here to see how to stop Nvidia Optimus from eating your battery:
http://www.junauza.com/2014/03/how-t...ntu-linux.html
http://www.thinkwiki.org/wiki/Switchable_Graphics

Note the second site: Thinkwiki is a great resource for Thinkpad+Linux information.

I thought ubuntu-based distro's had a working bumblebee setup so that Optimus worked correctly now?

I have the Optimus model of the Thinkpad T430. Optimus can simply be turned off in the bios, and the computer will work very well.
Here is a link that explains how to do this.
http://support.lenovo.com/ca/en/documents/ht062424
You can either switch it Integrated graphics like i have (this will get the best battery life), or you can use discrete graphics, and install Nvidia drivers ect.
OP, Don't let Optimus deter you from the Thinkpads.

Certainly not! They're excellent, and anyway they're not the only laptops with that technology. But it is as well to know that Optimus exists, rather than posting "why does my new laptop use so much power?"

Posting to confirm that the Lenovo Thinkpad T420 is compatible with Linux Mint.

lenovo t420 ok for linux mint 17.3 & 18
 

I bought one about a year ago and it runs Linux Mint 18 although sometimes it freezes, I clear out file system/tmp and .Cache. With Linux Mint 17.3 no problems and also works well with Windows 10. Enjoy!!!

Mine has i5 intel cpu and Intel HD 3000 graphic card.