Hi Beetle, that's a kind of weird crash. But I see from your dialog title there that you're using the Mar-17 v3 beta. I've just released a brand new one a couple of days ago, please try downloading the new one from http://moi3d.com/beta.htm and see if that one works better for you.

Also the moi_report1.zip file that you attached is of zero size, that may indicate that your problem is related to running out of memory. If MoI runs out of memory while trying to do some operation it could have weird side effects and also not generate proper crash reports as well.

If you are working with a particularly heavy file that is close to running out of memory there are some display settings you can adjust to reduce memory consumption, go to Options > View > "Meshing parameters" and change the "Mesh angle" setting to 25 degrees, and uncheck "Add detail to inflections".

That will make a rougher looking display mesh but will also reduce memory consumption by quite a bit on heavy files.

The default display settings generate pretty dense display meshes which look nice but can consume quite a bit of memory if you have a lot of little curved pieces or just a very dense model.

- Michael