To Jade for the initial solution which definitely got me looking in the right direction. This might be preferable if you have Saved Folders and you don't want to have to reenter all your email accounts, etc. Then under Connecting to Windows Live Services select Stop signing in. Once Windows Live Mail is open, go to tools, and then select options, under options select connections. I then restarted Windows Live Mail and it booted up fine - with all my email accounts intact, including all my saved folders, etc. To stop your calendar in Windows Live Mail from syncing with send and receive bring up the client. although, instead of deleting the entire Windows live Mail Folder as suggested above - all I did was delete the 'Calandar' folder inside the Live Mail Folder (which was supposedly corrupted in the error message). Yes, this worked for me on Windows 7 as well.

I think Live Mail creates a whole new uncorrpted LIVE MAIL folder when it can't find the original.

Now you can re-enter all your email settyings/accounts. On Windows 10, the Calendar app lets you connect third-party calendar services, such as, Microsoft 365, Google, Yahoo, and Apple iCloud, to manage and stay on top of your events using. > I then started Windows Live Mail and it started up fine. > then I REMOVED the entire Windows Live Mail folder ( you can make a copy also to somewhere else JUST-IN-CASE but make sure you DELETE the original 'Windows Live Mail' folder from the original location.) Windows explorer goto > USERS > (your user name) > AppData > Local > Microsoft

Windows live calendar service error