How to change Outlook 365 default Data file (it's an ost-file / smtp-mail)

[kiddingguy]

I am having an issue changing my default data file, when I try to make the one I would like (also set up as default in Email accounts) default I get this error message:

 

"The selected Outlook data file (.pst) format cannot be used. Outlook data files (.pst) must use the same format as offline Outlook data files (.ost). Select a matching Outlook data file (.pst) or turn off cache mode in the Account Settings."

 

I am using an ost-file (as part of a SMTP-emailaddress); mail is hosted on my own domain via mail hosting (not via my ISP).

Why is this not possible? And how can I set this up, so that Outlook (as part of O365) is starting up with this file, and thus my mails shown?

 

Or can't this be done?

(because I read this thread here...)

[goretsky Supervisor]

Hello,

Have you tried importing the .PST file and then exporting it as .OST from the original Outlook installation?

 

Regards,

 

Aryeh Goretsky

 

[limok]

.pst file is where you would store an offline archive of your emails. The .ost file is the local cache of emails that are coming in live to your mailbox. Turning off cached mode would remove the use of the .ost file but isn't recommended especially if you're on o365. 

 

You wouldn't deliver email to an offline pst file. 

 

What I think you're trying to ask is that you want the pst file to display in Outlook. To do this open Outlook, the File - Open - Outlook Data File. Find your pst and it will then display on the left side.