Getting 6410 protocol error during hotsync - Palm Treo 755p Smartphone

SOURCE: Connection is lost (6410)

As previously stated a 6410 error is a comunication error between your Palm and your computer. Uninstalling and reinstalling Palm desktop will do nothing to rectify your issue. You say it stops on recognizing handheld. Do you have another Palm connect USB adapter to try or another computer that has COM ports on it so you can perform a serial HotSync? Under the current configuration you will not be able to perform a complete synchronization. You have a week connection between your Palm and your computer.

SOURCE: Treo 755p Getting Stuck During HotSync

If you have another computer you could try installing the software on that to see if the Treo will sync.
This would determine if it's a computer problem or if it's your Treo.

When you unchecked the datebook to sync after uninstall/reinstalling, was it able to sync then?

I have had other palms get hung up to a certain point during the sync, but uninstalled the program or disabled it from syncing like you tried and it usually works.