What is Outlook Data File in Outlook 365

W10 ver, 20H2

I have just switched from Outlook 2010 to 365 and am confused about the appearance of an folder named "Outlook Data File" and "Outook.Pst shown in Outlook. My original three .pst files are still there and Outlook seems to work just fine. Outlook Data File shows as default.

Would someone please try to explain the purpose of these two new files and can/should I remove them or just ignore them? Likewise can I remove the original set of .pst files?

I know I am getting in over my head here.

Thank you.

Maybe this will help?
https://support.microsoft.com/en-us/...2-f331f60e2790

garyb0125 said:

Maybe this will help?
https://support.microsoft.com/en-us/...2-f331f60e2790

Thank you. Anything that provides accurate info certainly helps and that qualifies. However, it doesn't answer my poorly phrased question. From where did that Outlook Data File.PST file come. It was never there until I upgraded to Outlook 365.

JJG10 said:

Thank you. Anything that provides accurate info certainly helps and that qualifies. However, it doesn't answer my poorly phrased question. From where did that Outlook Data File.PST file come. It was never there until I upgraded to Outlook 365.

I use Outlook 2019 so I can't answer your question precisely. Have you opened the file to see what's in it? In Outlook 2019, you go to File-> Open & Export -> Open Outlook Data File -> browse to the .pst file.

Hi there

@JJG10

Not sure if this is the 100% correct answer - but here goes.

Until Outlook 2016 or so all the data content in outlook was contained in a .pst file. If you use IMAP rather than POP3 then even if your mail was maintained on the server there were always some things that would be held on a local PC and these were generally in a .pst file.

Often people might want to save data from IMAP / EXCHANGE servers on to a local PC for archiving / copying etc and this data is in a .pst file even though the main OUTLOOK data files are no longer held in .pst files.

OUTLOOK/365 has loads of people converting from systems as far back as even OFFICE 2007 so compatability with the old .pst files is still maintained.

If you don't need these files then OK but they are good for archiving / copying to another computer.
etc.

I really wouldn't worry about the creation of a .pst file --if it's not needed it won't have anything significant in it and won't be large anyway. Just ignore it.

OUTLOOK 2019 / 2016 and /365 can all open, handle, read and write to .pst files without problems so you shouldn't lose any data converting from Office / OUTLOOK 2010.

Main data files now in OUTLOOK are I think in .osd files -- no idea -- I use OUTLOOK 2019 with IMAP and save any data from the servers into a .pst file which can be opened / read / write etc just as any of the other IMAP folders - the only difference is that the .pst file is stored on the local PC and not on the email server. The .osd files have info about the IMAP files on your email server.

I hope nobody here is using POP3 any more of course.

Cheers
jimbo

Spot on Bimbo, as usual!

Seems like I can remember reading about the change to IMAP several months ago but I didn't pay much attention to it. My bad!

That leads me to wonder about having my two other Outlook machines set up as POP3 and the current one as IMAP. Will that offer any problems between the interaction of the three?

Thanks again and I will mark this thread as solved.

jimbo45 said:

Hi there

@JJG10

Not sure if this is the 100% correct answer - but here goes.

Until Outlook 2016 or so all the data content in outlook was contained in a .pst file. If you use IMAP rather than POP3 then even if your mail was maintained on the server there were always some things that would be held on a local PC and these were generally in a .pst file.

Often people might want to save data from IMAP / EXCHANGE servers on to a local PC for archiving / copying etc and this data is in a .pst file even though the main OUTLOOK data files are no longer held in .pst files.

OUTLOOK/365 has loads of people converting from systems as far back as even OFFICE 2007 so compatability with the old .pst files is still maintained.

If you don't need these files then OK but they are good for archiving / copying to another computer.
etc.

I really wouldn't worry about the creation of a .pst file --if it's not needed it won't have anything significant in it and won't be large anyway. Just ignore it.

OUTLOOK 2019 / 2016 and /365 can all open, handle, read and write to .pst files without problems so you shouldn't lose any data converting from Office / OUTLOOK 2010.

Main data files now in OUTLOOK are I think in .osd files -- no idea -- I use OUTLOOK 2019 with IMAP and save any data from the servers into a .pst file which can be opened / read / write etc just as any of the other IMAP folders - the only difference is that the .pst file is stored on the local PC and not on the email server. The .osd files have info about the IMAP files on your email server.

I hope nobody here is using POP3 any more of course.

Cheers
jimbo