How to remove stripped bolt

I installed an aftermarket head unit in my 09 a few years ago and now want to replace it but the lower right side bolt (1 of the 4 that secure the HU) is stripped. I don't mean the hex head is stripped, the threads are stripped. It turns right and left with no resistance at all and doesn't tighten or loosen. Hoping it's the bolt threads that are stripped and not the mounting hole threads but don't know at this point. What would be the best way to remove the bolt. Can anyone offer some advice?

 

I've had a few as described and if it is just the bolt threads I've had luck pushing on the backside of the bolt while trying to turn it out. This would keep pressure on the bolt and hopefully allow it to pick up on some threads that are not stripped out yet, once it does the bolt will turn out as it normally would do.

Alternatively if it's a bigger problem you can carefully dremel off the bolt head and send the bolt out the other direction.

 

Stick a straight blade screwdriver between the back of the head and the surface behind the head. Gently twist the straight blade as you turn the stripped screw counter clockwise. Is should back out.

 

If you have room, unscrew it with long needle nose pliers while pulling.... you should be able to catch better threads and it will come out as it should.

 

If it spins pretty easily I've had luck with bolts like that by holding it with a pair of pliers and pulling towards me while turning it. Pretty much the same idea as pushing from behind or putting a flat head under the bolt head

 

Thanks guys. Already tried all that with no luck. Not even close to grabbing. Just spins.