Is there a way for this to be enforced at server level? (Otherwise they won’t trust us to turn it off…)
I’m not an exchange server expert by any means, but my guess is probably not.
[Petty correction]
It’s an OST file rather than a PST file. (Don’t believe me? Check %AppData%\Local\Microsoft\Outlook)
OST - Offline Storage Table. Cache file for cached exchange mode
PST - Personal Storage Table. Used to store emails away from the mail server, often for archiving.
Using Outlook without cached exchange mode (called Online mode) is not a good idea. The performance will be unacceptably poor - each email has to be read from the server when you open it, with a delay of 1-5 seconds from you clicking it to it appearing.
Online mode is OK when you have fast local connection to the exchange server. Over the internet it will never be fast enough.
Generally speaking it is possible to use Office 365 with Outlook. I would be interested in the licensing implication of using desktop Outlook with Office 365 - I have not come across this before. That’s not to say that it wouldn’t be disabled for security reasons.
Sadly it isn’t possible to disable cached mode from the server-side - has to be done via Group Policy settings on the client.
When using OWA in Office 365, additional mailboxes are mounted in the navigation pane, similar to how multiple accounts in desktop Outlook, which does make managing multiple mailboxes much easier, as you don’t have to open a separate window for each account.
That said, when logging in, additional mailboxes are collapsed by default and need to be clicked on to expand before folders and number of unread items are visible.
My speculation is that access to additional/role accounts will given to personal accounts, and we will log in with that personal account only. So only one password to remember and update when it expires…
That is my understanding of the plan.