Split from this thread.

I have just had the same problem - calendar entries completely disappeared with no warning. This data is important and I can't afford to lose it. Am using Windows Live Mail (WLM) 2012 with Windows 10 x64 latest builds and up to date. Updates did not create any problems and data was there a couple of hours ago. E-mails are still there. Have uninstalled and reinstalled WLM 2012 with no effect - have everything except the calendar.

The system is NOT synched to anything and has never been. The Windows a/c used are all local and there is no sign on anywhere (except this forum) relating to an MS account. I don't use any of the new Windows 10 apps - only traditional, installable applications (MS Office 2010, Adobe Photoshop Elements and the like). I wouldn't even have n MS account except to use this forum to try to get an answer.

I've done a restore of the backed up AppData directories but still no calendar entries.

Where EXACTLY is the calendar data stored in the AppData structure and what are the names of the relevant file(s)?

Once I know what I'm looking for, I should be able to get the data from the backups. I'm assuming here that Microsoft itself hasn't sabotaged WLM to force people onto the useless Win 10 app and that WLM will actually still recognise the calendar data stored in the local drive.