Mail (4.6) OSX 10.6.8 problems with Office365 Exchange

Hi all,

Recently our business mail server was switched from Outlook to Office365.

My former Mac Mail.app (v4.6) was using an Exchange account dbxprd0210.outlook.com without any problems. Last week we had to switch, so I've re-added my account again to Mac Mail (to keep my old inactive account renamed for history purposes), just entered my e-mail address and password, and the rest was done automatically, this time using Exchange account outlook.office365.com which seemed to be working just fine.

Until....... until I restarted my Mac. All of a sudden, the inbox was empty! Also the Deleted Items were gone, as were the Sent Items. Checking my mailbox through webmail shows all my mails, so they are not completely deleted thankfully. I've sent a test e-mail from another account and it appeared in the webmail, but not local. I tried re-adding my 'new' account again, and now the new e-mail appeared on my Mac. But, it was the only e-mail there, no history was showing.... And after stopping Mail and restarting, again all is gone...

I tried several things to find out what causes this problem and get this baby on the road again:

• Show account info - it's connecting, but shows 0kb and no mails (only a few Sent Items, from testing)
• Rebuild account - nothing really happens, no new mails, same problems
• Connection Assistant status - shows connected with server just fine and logged on
• Synchronize mailbox - nothing happens
• Setting mailbox online > offline > online - nothing happens
• Restarting Macbook - no success either
• Checking MacHD>Library>Mail>EWS Exchange Account - can't see anything wrong here, mails are saved as *.emlx files

  what IS strange, after restarting Mail.app no mails show in Mail, but the former emlx files are still there!

• Added my Exchange account as IMAP - this seems to be working partially

  but it's not saved locally, so I have to be online, and I'm missing all my iCal items - not a real fancy work-around 😟

• Deleting and re-adding my Exchange account works, only for new mails without history, and only until Mail.app gets restarted

Does anyone recognize this issue, and knows how to fix this??

I've been struggling for days now... 😕