OS X (Mountain Lion) pre-installed.

Mail version 6.2

Incoming Mail Server: imap.tools.sky.com

I have searched the 'net and although I have found others with the same issue, nobody has come back with a solution yet:

I can watch e-mails come into the inbox and sit there (with the unread mail digit next to 'Inbox') then after a few minutes they will all then automatically move into the 'Trash' folder, or even go there directly (bypassing the Inbox)

There are no active rules set up apart from the factory installed: 'News From Apple'

It's now getting to the point of me considering installing Outlook!!

It's not a setting on sky is it? Might be worth checking as it will just be doing what the imap settings are telling it to do. Log on to sky email through safari and check your settings.

I could not see any imap settings on Sky referring to deleting e-mails in to a trash folder (nothing was changed when I moved over from Outlook to Mail)

Not sure why it was doing this but I changed the e-mail settings from imap (which the Mac configured automatically) back to POP3 (which is how the PC was set up) and it is behaving normally again.

I was going to suggest that :think: (honest!!!)

Glad it's sorted, and I hope you\re getting on the the iMac.

Loving it so far.... once I got my head around everything being in 'the wrong' place

You'll never look back, I promise!

Not sure why it was doing this but I changed the e-mail settings from imap (which the Mac configured automatically) back to POP3 (which is how the PC was set up) and it is behaving normally again.

IMAP will sync with the server, POP will not. If it's not happening with a POP setup it sounds like the sky account is trashing read emails (ie ones you've downloaded) automatically. Apple Mail is then seeing that it's moved on the server and making the change locally too.

When you get a new mail via POP in Apple Mail - log into the sky webmail and see if that email is in your inbox or in the trash on the server side. If it's in the trash then it sounds like either sky or Mail is telling the server to delete an email after it's been downloaded.

POP will be fine until you want the same email on your phone or another computer, then you'll end up with copies of mail on both devices with different read markers and deleted on one but not the other etc. I found it a nightmare until I switched to IMAP. But if it's just on the one computer, and always will be, then stick to POP for ease of use.

Sounds like a filter on the sky mail, or an incorrectly mapped folder sync.