[khunhorm]

Whenever I accept a meeting invitation email, the windows 8.1 default mail app immediately delete that mail from my inbox and that mail can only be found in deleted folder. This is really annoying. Is it possible to fix this? Please help.

[Pete]

This is how it works in outlook as well and is standard behaviour. When you've accepted the invitation, you'll have the entry added to your calendar. You can move it out of the trash into your inbox if you really want to.