I have a client we have recently migrated to Office 365 (Exchange Plan 1).
One of the clients has some older mail in their Inbox which has between 30 to 90MB attachments each (that they have managed to send to each other internally - the old exchange was 2003) - Outlook is continuously trying to send these emails to Office 365 which fails as the message is too big.
Haven't an issue with that and my understanding is that this would just remain in the local Inbox and wouldn't be synchronised, yet all I see is constant re-transmission of the same email over and over again - which also means that the Inbox takes forever to update.
Is this expected behaviour or is something amiss going on as it is making the whole experience of cloud office 365 untenable for the customer as they cannot use Outlook.
I suspect that out of all of the 10 clients they all have the same issue to a greater or lesser extent.