I guess I've been lucky, I've worked for days and days on my vehicle with the 7424XP, without the handle attached, and haven't had a problem. But now I guess I'll go buy some bolts just in case. The last thing I need is for the thing to fall apart and maybe scratch the vehicle ...
Hmmm, I read elsewhere that if you operate the PC without the handle attached, the top will come loose. I haven't had this issue (knock on wood) but maybe this is what you're experiencing...