Serious Mouse Problems with Mountain Lion

Bad USB cable, pinched cable on the mouse, defective USB cables and extensions, trouble with hubs, but also yes I found I needed Disk Warrior. It found what Disk Utility can't.

I like to clone and test on clone and give it a good going over - safe too.

Yes, I'm having trouble as well after the upgrade. My mouse pointer disappears after some time. Using the CMD->TAB brings it back again. This occurs with a wired MS mouse and with the Magic Mouse. Though it is kind of magic, it's very annoying.

Disk Warrior fixed a problem but I and others have often found the Apple USB cables and extension to be faulty.

If it happens with anything plugged into the (same) USB port that points to the logicboard.

Hubs can be an issue, and keyboards are a hub, as is the Apple Cinema display

Bad disk drive. So clone it and zero it and repair.

Rule out Is it hardware? is it software? Apple wanted to blame anything but the real cause, it came up during 10.5.2 and I was shocked - and disappointed the guy I was talking to really wanted to blame the MS Optical Intellimouse (it was not and I had lots of Apple and MS mice and keyboards to test with).

It was OS X but also Mail - its sync services and the convoluted aliases it builds for all the local mailboxes. which I still don't understand.

Apple makes no promise of reading things posted here, and NEVER responds here.

If you have a problem (regardless of whether you think it just needs a software update), you should call Applecare or make an appointment to visit your local Genius Bar.

I've experienced a mouse problems too on Mountain Lion...unbelievably jittery when connecting my Macbook Pro to a secondary display via HDMI. Pretty much unusable unfortunately.

The trackpad on the laptop seems to work okay, but I don't see myself using it while using the secondary display.

Hopefully an update will be released soon because this occurs with both my Microsoft wireless mouse as well as my Logitech one.

For giggles, I tried using my wired Logitech G9 mouse...works like a charm. So whatever my issue is, it is related to a USB based wireless mouse both on the Microsoft and Logitech side.

So the conclusion in your case is that maybe something that was not part of Mac OS X (installed earlier and carried forward) was the problem, or possibly there was something damaged.

I've been having problems with my mouse behaving like I have double clicked something instead of single clicked. I also have problems with sub menus I click appearing and immediately disappearing when I try and click them. Very annoying. It takes a concerted effort to persuade the menus / sub menus to remain on the screen. Need to hold down the click button to keep the mouse of screen. Problem is it is intermittent and hard to pin down the cause.

Perhaps your mouse is sending rapid multiple clicks.

Have you tried adjusting the double-click speed?