Help! Mail is deliberately deleting my emails!

[L-Viz]

I received an important email with attachments 3 days ago, now it is gone! Cant find it in the trash or junk folder! Im using an iCloud mail account.

Second problem is, that I sometimes see a mail for a second and then it is gone, automatically deleted, cause my mac thinks it is junk. Well it isn't! Can anyone help?

 

[mj_]

Junk isn't deleted, it's moved to the Junk folder.

 

[Gregg2]

In Mail Preferences > Junk Mail, you can instruct the app to leave messages it marks as Junk in your Inbox.

It's interesting that you know Mail is doing this on purpose. I would have held out the option of a Senior Moment, for Mail, not you. Or, maybe it was acting out due to excessive stress. Did you consider giving it a Time Out?