I guess I'm part of a group of people that his computer have this balloon cursor a couple of times a week. I have a Mac Mini mid-2011 with the mountain lion upgrade included but downloaded. I didn't want to loose the 20$Can offer about the upgrade. I just hope they'll fix this soon.
I did some digging:
Booted Mac mini with D pressed in order to get the diagnostic screen. Ran it 5 times on extended check. Came clean every time. But it tooks me 20 reboots in order to get that diagnostic screen. The mouse and pad didn't work in the diagnostic. Had to make it work with the keyboard.
My system:
I have Mac mini basic (600$Can) upgraded with SSD Kingston V200 250Gb and a memory upgrade to 8Gb. I have Apple Magic Mouse, Keyboard and touch-pad connected via Bluetooth. I'm using it in French Canadian version. The keyboard is also french canadian.
What I did after installing SSD:
Installed from Time Machine backup option when booting with an empty disk.
What I did recently:
Installed last friday the OS X server for 20$Can. It didn't change anything about the problem.
Recurrence:
It seems to happens a couple of times in a row and after sometimes in the week. When I play StarCraft II, it frozes the computer one out of three times. In that game, it happens often after the login; sometimes after quit.
I hope those informations are useful and a solution can be found sooooOOOOoooonnn.
Regards.