When you say it "cannot sync", can you give any errors, or screens that your desktop PC displays from Desktop Manager? It's hard to diagnose with the very little detail you offered.
Have you set up your Intellisync with Outlook?
Click on the CONFIGURATION tab at the top, and click the button CONFIGURE SYNCHRONIZATION. Make sure each option is matched to Outlook as you desire.
If still not working:
Look at your Desktop Manager, Help, about
: what version are you running? If it is anything 4.1, etc., go to this website and download the 4.2 Service Pack 1 version... https://www.blackberry.com/Downloads...93E4F3BB068C22
Install that, follow the instructions, reboot your computer and pull the battery and reboot your BB. Try sync again.