One of the many errors that users have encountered in the last 20 days since Windows 10 came out is 0x80c8043e, which appears when trying to sync Mail and Calendar after upgrading to the new operating system.

While Microsoft hasn't specifically provided any guidance on how to fix this issue, posts on the company's Community forums reveal that quite a lot of users have actually come across the problem, and without an official workaround it's not difficult to understand why so many people turn to various unconfirmed methods.
Fortunately, there seems to be a way to fix error 0x80c8043e in Windows 10 because the problem appears to be caused by one of the three cumulative updates that Microsoft has released until now.

How to fix it

So basically, the easiest way (but not the best and you'll see why in a second) is by removing the KB3081436 update completely. And yet, you're not recommended to do that because the update also comes with other fixes and improvements, but if for some reason you really need those apps to work, here's what you have to do.
Right-click the Start button, launch a command prompt window with administrator privileges and paste the following command:
wusa /uninstall /kb:3081436
One of the users who posted on the Community forums also discovered an alternative method that also works, but no other Windows 10 adopter can confirm it for the time being:
Here's his message in full, but try it at your own risk:
“In order to get Email and Calendar app work again you need to create a new user account in your Windows 10. After you do that -> Transfer all your data and files to the new created account (apps will be set to default in the start menu but software and games installed in the old account will remain installed in the new account). After you done transfering all your data and files delete your all account and set the new one as Adminstrator and connect it online to your Microsoft account in settings->Accounts.”