Having a PDA and Windows Mobile is not always synonymous of "ease of use". To cancel all appointments and all contacts previously synchronized with Active Sync is not simple. There isn’t a button, an hidden key, a native tool, perhaps with 200 password, that will clean up your listing without drive your pencil to the hard reset (meaning the PDA back to the roots, when you pulled out out of the box, and then without a bit of software that is not the OS preinstalled).
The alternative, the most simple, I’ve found is to synchronize your PDA with a false Outlook profile.
Of course, even here things aren’t immediately, while creating a new profile on Outlook, the database of contacts and calendar, PDA realize that the source and destination aren’t the same. Nor replace the file with a new file with a blank work. The solution (not immediate but effective):
1. Restart the PC you use for the sync process (so no file is pending or in memory)
2. Create a new file Outlook (pst) completely empty
3. Copy the old file (for backup purpose)
4. Open Outlook, canceled all appointments, and all contacts
5. Synchronize again PDA (at this stage the profile match and Active Sync did not complain)
This will cleanse the PDA. Obviously at the end of the process, after the handheld detached and closed the Mobile Device Center, we must restore the backup copy made in paragraph 3 to get all the data back.
If someone knows a shortest way, a welcome comment.