Stripped Mounting Holes on Top of Built In Microwave

Contact the manufacturer. They should be able to provide you with a replacement. You will most likely have to replace the bolt as well. Or you can use a tap, it's easy but you will probably have to repair the bolt as well. You can use the good bolt to determine the correct size. If you opt to take apart the microwave you will probably need a t15 torx security screwdriver as well. Most microwaves use them for some of the screws. Be wary of electric because some capacitors will hold a charge even without power.

You not only need to clean up the threads on the nut, but the bolt as well. Easy enough to do. Since it's already tapped you just need to run the correct size tap through the damaged nut and bolt. Just enough to go through to the other side.

Alternarively, I sometimes use a different bolt for the damaged nut and vice versa. This takes a lot more experience as most of it is feel to see if the threads are still cross threaded or if it's going to be ok. I would do this with the microwave not mounted so you are not trying to do several things at once.

You should also be able to purchase a new set of fasteners online.

A good trick is putting for any machined fastener in is to screw the screw backwards at least one revolution. This sets up the screw for the best chance of going in straight.

So when you say the correct size tap, do you mean use a tap that is the same size as the current bolt, not any bigger? Just running a tap through the damaged hole will fix the threads? If that works, it would be awesome because right now I've got a very unhappy wife!

Looking at the bolt, it definitely looks like I'll need to replace it, the first threads or two are stripped on it as well, so either way, looks like I'm ordering some replacement parts....

Make sure you use a bottom tap and just buy a new bolt.

Sorry, for all newbie questions, but say I get a tap that is the same size as the existing threaded hole (1/4-20), using a bottom tap, I would would put it in there as straight as possible and then and proceed to twist it all the way down through the length of the nut, leaving me with a newly threaded hole of the same size?