Active Sync issue
 

I am about at wits end here as the calendar and contact list are two of the most important items I use this unit for. OK. here is what I have done so far... ( twice!). I deleted my partnership on both the PC and the PPC. I did a hard reset on the PPC. Disabled my firewall on the PC. Established a new partnership. Checked all settings on the PC and PPC. Re-synced the PC and PPC. Result: not ALL of my contacts and calander items will sync... only some... I would say about 80% of them. If I delete a contact on the PPC it will automatically sync and delete it on the PC as well. And when I create a new contact on my PPC it will automatically sync and place it on the PC as well, however when I create a new contact on my PC it will automatically sync but will NOT place the new item on the PPC. ](*,)

i think there is a setting in there that is is like 'phones calendar overites pc calander' or 'pc calender overwrites phones calendar'. same goes for contacts. if u hard reset u need to make sure it synce down to the phone not up. i hade all my contacts on pc and phone. did rom upgrade. went to synce my contacts back to my phone and instead of my phone getting all the numbers, my phone cleared out my outlooks contacts list to nothing! had to manually reenter them on pc

Active sync
 

Id remove active sync from your PC and start again, as when you first Sync the XV to a PC it will ask will you replace the items on the desktop or on the PDA, so that may be a bit screwy.
You say it only put on 80%, does it stop after that or just say its finished?
Also try opening USB to PC in Settings>Connections and disable the advanced network functionality, as I was having a real issue getting Active Sync to work with V6 rom. Once it was disabled worked a treat.