Undo malfunction in 3dsmax 2009

Okay, encountering a pretty annoying error here.
Put simply, the undo in 3dsmax is not undoing what I want it to.
I accidently pressed “delete” when I was trying to press page down. Naturally I pressed CTRL-Z afterwards. However, instead of undoing the bone deletion, it undid the last change I made to a completely different bone (changing the animation, fyi)! I’ve tried google, to no avail. Does anyone know how to revert this?

Sorry to have to resort to this, but a quick answer would be extremely appreciated. I can’t really close 3dsmax at the moment since I would lose any hope of regaining the bone.

This has happened a couple of times before, but had no real impact (since I didn’t accidently delete anything).

ps. If it helps, I was using Auto Key at the time.

Few more bits of info:
It almost certainly isn’t a RAM error, it’s been happening since I started today. Also, I’m not running any custom scripts (I think).
Also, it seems that it saves changes in animation when done in the Curve Editor, but does not save changes done to any bone or changes in animation made with auto key.

Last resort would be to reinstall. You probably accidentally changed an option somewhere.

:doh:

Save a duplicate copy, close, then re open. I’ve had this issue before.

Something like this happened to me as well. I have no idea what it is, but sometimes 3DS Max just doesn’t let me undo at all. I use the keyboard shortcut and also the menu (Edit > Undo).
For all I know, I just pressed a keyboard shortcut that disables the undo option - pretty useless if you ask me :stuck_out_tongue: