I had a calendar synchronization for several weeks. My Windows mobile device could not sync properly with Microsoft Outlook. In order to wipe out the calendar, the above process should be followed:
1. Connect your device to the computer
2. Open Windows Explorer
3. Browse Mobile device
4. Browse My Windows Mobile-Based Device
5. Find the file called pim.vol
6. Rename it to pim.vol.old
7. Unplug your device and do a soft reset
8. All the calendar entries and contacts will be removed
9. Delete the pim.vol.old volume
10. … and resync the device
