[kuznets]

It seems there are times when my Z10 reverts back to some stage in its life and forgets what's programmed. This morning my calendar notification went off and it was not what was programmed. I checked the settings and they were totally different than what I had programmed. I tried to set them to my preferences but couldn't access the files on the media card. So I removed the battery and then installed it again (a reset as I understand it) and voila everything was ops normal. And this is not the first time this has happened. So, why does the Z10 do this? I change batteries (I have 4) every several days when the power usage of the phone requires it. I have all the latest updates and few applications.

[tsac]

Calendar entries are NORMALLY on the cell phone's internal memory not the memory card.
Try pulling the memory card and only using internal memory for a few days or how ever long it takes to see if it helps. If you using a third party app for calendar use try the base calendar on the Z10.

I have two Z10's and never had any issues with calendar except when my computer over wrote the entries on the phone and added old data. That was caused by me not selecting the proper sync options.

Also do not let the phone battery power go so low that it may cause issues. It seems like your changing battery's and the issue is resolved.