I'm downloading it from work PC, that's currently running Win 7, using Chrome, don't suppose it'll make a difference but worth a shot. Will delete everything Line 6 from my PC, reboot and start again. If that fails, I'll try my wife's laptop.
Weird thing is, after I'd update on Saturday, but restarted using 7 & 8 as that's what it said on the screen and Helix Edit was working then in the brief time I tried it.
Since then, all I've done is reboot the Helix doing the 9 & 10 thing. Didn't touch the PC, so nothing has changed that side, all that's changed is whatever the Helix does differently between 7 & 8 and 9 & 10. Tried it last night and got the crashing.