Comment 10 for bug 958174

Your mouse may be bad, but mine is not and I exerience the exact same symptoms on 12.04 (64bit fully updated as of 2012-03-28. Many times the mouse is not working at the lightdm login page. Mouse & Unifying receiver work just fine with 11.04 & Win7 on the same machine.

3.2.0-17-generic x86_64

046d:c52b Logitec, Inc. Unifying Receiver

Mouse is a Logitec M505.

Removing the USB Unifying Receiver & plugging in again sometimes works. Rebooting sometimes works. Again; only problems when booting/rebooting to 12.04 - mouse & receiver work fine when booted/rebooted to 11.04.