I believe it's sp2.1. (at work now) Did you check in help/about?
I don't think SWx 2015 is supported officially until sp5.
Had the same problem ( student version) with the add-ins on win 7.
After doing all the fixes, uninstalling and reinstalling, still no add-ins.
Had to uninstall, clean out the registry, reinstall and Bingo!
Good Luck - Donald
Ok, thanks for your answer!
I thought I did check the version and the about-section and just couldn't find the SP at first. I tried again, but to no avail, I can't find it... But I believe your SP2, sounds probable. And I understand that the not appearing simulations is not necessarily a win10 problem, right? The rest seems to be working for now, so maybe the student SP is not completely breaking SW on win10. I haven't tried everything so I will see when I need it more.
I will try your steps for the add-in problems. I'm not really sure what you mean by cleaning out the registry, but google is my friend (sometimes...). The add-ins are nearly always a problem in my surroundings, unfortunately...
Edit/Update: It's working. Tried a registry clean up (at least I think I did, with ccleaner). I disabled the kb-update, remove/reinstalled SW, then I enabled the kb again. I'm started it in compatibility-mode (win8) and it looks like it's working. Thanks!