Not sure how this might affect a USB mouse, but mobsync.exe is a Vista service for removable mass storage devices, so there might be a connection.
More about mobsync.exe here;
Scroll down the page to see how to change this service from automatic to manual. A reboot might be needed for the change to become effective.
See if that helps.
I think I've pulled out my last bit of hair trying to fix this problem myself.
About a week maybe a bit less ago, I was playing a game and started to get a bit of mouse freezing very brief here and there. I just kind of brushed it off though as it wasn't bothering me very much. Now the past few days have been the worst. very sporadically my mouse will pause and show the round "think" circle will show up for about a second, sometimes 5 seconds. Right when it pauses, it makes the sound like I had just unplugged it, then about 5 seconds later or less it will make the sound like I plugged it in. I tried all the driver nonsense, that never worked. I tried updating windows, that seemed to have made it worse. Infact if memory serves me, it appeared right after I updated about a week or so ago.
Now, I opened task manager to see if I can find the culprit in the processes. Low and behold, as soon as the mouse lag starts, mobsync.exe (aka sync center) shows up, then disappears after the lag and "plug in sound" stops within 5 seconds afterward. It will do this very sporadically, there's no pattern to it at all, sometimes it will do it up to 4 times in a row. I've tried system restore back to 2 weeks ago but it gives me an error after it makes me reboot. I'm completely lost. I've googled the problem of course, with a few people having the same problem but it all remains unresolved. I'm going to buy a new keyboard and mouse if this keeps up, I just wish I didn't have to spend money for clearly something that's messed up in vista. And believe me I love vista, I've been using it for years (with a USB mouse, go figure), but this really makes me want to switch operating systems. Not because of a stupid mouse, but because of heinous programs they force you to install that can't be turned off. I've tried everythign in terms of optimizing, like defrag, and registry cleaners and anti virus scans. Here are my specs.
OS: Windows vista home premium x32
Video: ATI radeon X1650
Processor: Intel pentium D @3.00x2
RAM: 4GB crucial (only 3.2 being used because of OS)
Mouse: Logitech standard optical USB mouse
HDD: Western Digitial 465 GB
Anything else I forgot let me know.
And, btw, my keyboard doesn't lag, it ain't my system it's silly sync center doing something with my mouse.