On my old laptop running Windows7 and Outlook 2010 all data are .pst-files I acquired a new machine with Windows 8.1 and Outlook 2013 and now all date are written in .ost format; I had NO problem at all to set it up with my email account, BUT... NO way to read or import my older mails, contacts nor data; at all attempts Outlook 2013 returns me an error message telling it can't run PST and requires OST only ! Please, is there a solution to read and combine my older messages, contacts and data ??? Thanks a lot for your help !
You can open your pst file in Outlook and copy the content to whichever account is using an ost file.
Thank you Mike, but as I wrote, it's IMPOSSIBLE to open any .PST-file; Outlook always return a error message accepting exclusively .OST-files !!! ...
OST to PST Converter Software This is very simple with third party utility, try this tool osttopstapp.com this will help you to convert you file from ost file format to Outlook pst file format.