Activesync issues are mostly related to USB driver errors in windows and not activesync or the device. In using Wndows CE over the last 8 years starting with an Ipaq and now a Mogul I have constantly been frustrated with the loss of sync ability. Multiple Microsoft help pages and years later, the only working solution is to uninstall the USB driver for the mogul manually (using software for XP like this one.....
http://forum.ppcgeeks.com/attachment...7&d=1207752494) or by locating the windows mobile device driver in Vista and manually uninstalling it.
Each of these methods has returned sync ability when it is lost for no reason and does not require a reboot of the PC, does not require a soft or hard reset of the mogul.
Also shutting down activesync with killsync is helpful in clearing all offending traces of the failed driver loaded in the memory.