htc sync cuts off when ROM update tool opens

[adz63]

ok im on 3 and have goldcarded my sd now i have to downgrade ROM to put a custom ROM on..

it syncs no problem but when the update tool starts to run it un-syncs me therefore not being able to downgrade i have searched the net and cant find no solution and cant find one on here either ..

any sugestions would be great .

ps all drivers including ADB have been installed and working and i downloaded the latest sync program too