sekullbe

I'm pretty sure you get an alert on loading the save that flying ships X and Y were not loaded because of incompatibility, but I haven't seen that recently. I don't mind fixing the save or doing the plugin shuffle- the weird thing for me was the way the VAB just broke. If I have time I'll try to do enough testing to write a real bug report for KSP itself if that's what it is.

I just had a weird problem that's probably not caused by 1.0 but is related to updating. Many of my saved ships have an engineer part on them from the previous version, so I can't load them in the VAB. When I try, I get the warning popup that the ship can't be loaded and then the whole VAB just stops working right. The exit button lights up but does nothing when clicked, I can click Load and see my list of ships, but can't actually load them. 'New' and 'Launch' do nothing. Since I can't exit the VAB, I have to alt-tab and kill the process. I don't yet know if it's caused by other mods (mechjeb or KW), but just a word of warning for anyone updating. I'll probably install the old Engineer, fix my rockets, then go back to 1.0.0.0.

I had the same problem, and for me it was old detritus from a previous MechJeb installation. I had ancient MechJeb files in the Parts and Plugins directories. Once I cleaned those out, adding the AR202 module worked for me in both sandbox and career mode. I also had two AR202s in the Control menu; one must have been from the old install. I think I have a few ships flying with the 'bad' AR202, since they don't bring up the MechJeb menus, but if I build a new ship it works fine.