A new feature in Office 2013 is the ability to only sync a limited amount of data to your computer. This setting comes in the form of an amount of time. Only sync the last month, 2 months, 3 months… A lot of readers will have seen this setting if they’ve ever setup their own smart phone and I love the ability to have this option. I often run and have clients that run 3-6GB mailboxes and don’t want to suffer the performance loss by have that size of OST (Offline Cache)
I found out recently while upgrading an Office 365 Plan 1 Small Business Account to a Office 365 Plan 4 Enterprise account which requires a export to PST / import to PST that Outlook 2013 will only export the OFFLINE CACHED DATA ONLY! It will not download the entire mailbox and export it.
You must change the offline cached setting then allow Outlook to download the entire mailbox.
(This took me hours to do a 3GB mailbox only 256MB had been offline cached. Even though I have a 30MB/5MB connection Outlook will only use minimal bandwidth which is a problem, if you know of a solution to this please comment below)
A user needs to change Cloud Email accounts maybe changing Office 365 Plans which are different tiers or changing entire providers. If the user is using Outlook 2013 they export their email to a PST. Remove the old service and domain to setup the new service and domain. The user then uploads their PST data to the cloud and finds out they only exported the Offline cached data from Outlook 2013 and not the entire mailbox!
If you are moving to Office 365 I strongly suggest you use the Migration Tool which will have both exchange server old and new work together to transfer all your data and most your settings to the new service without the need for PST export/importing.
However, you can’t always doing this in the case above where you are changing Tiers within the Office 365 network.
Set Outlook 2013 to cache ALL DATA offline once this is done Outlook should say all folders are up to date… Then you can export the data to a PST file. The PST file size should be just smaller then the Mailbox size was in the Cloud. This information can be provided by your Systems Administrator or in the Exchange Control Panel/ECP.
I suggest you never remove your old email service until you’ve fully verified the new one with all it’s data.