Help! Blackberry Keeps Deleting Calendar Entries!

Dear All,

I am using a blackberry 9780 V 6.0.0.294 (Bundle 905 platform 6.5.0.54) with desktop manager 6.1.0.35 (Bundle 34).

I am encountering an unusual problem and I could do with your assistance.

My blackberry device keeps deleting calendar entries in outlook when syncing. I can clear the database and re-sync but then after a few days when I sync it says device will delete 'n' entries in my calendar in outlook!

- Device is set to keep appointments forever
- i have tried to sync "all" appointments and appointments within a range via desktop manager.
- I have cleared all my event logs.

I have reset my desktop manager configuration too, but it keeps happening. I have even run inbox repair tool on outlook to check for any errors in my PST file.

Has anyone else experienced this problem? Any ideas on where to start looking for a solution?

the only other thing I find is that every now and again my 9780 starts to run slowly - I have deleted all unnecessary apps from the device, I have plenty of free memory (205MB available on device).