PST Rescue
Does new Outlook support .pst files?
Short answer: only partly. New Outlook for Windows can open a .pst file, but only if classic Outlook is also installed and you have a Microsoft 365 subscription. Microsoft plans to move classic Outlook users to new Outlook from March 2027, so it's worth getting your archives into a format you can open anywhere.
What new Outlook needs to open a .pst
According to Microsoft Support, opening a .pst in new Outlook requires:
- classic Outlook installed on the same PC,
- the same architecture (32-bit or 64-bit) for both,
- an account with a Microsoft 365 subscription,
- and it isn't available on the ARM version of Windows.
Microsoft says it plans to add bulk import and remove the need for classic Outlook, and that after that it has "no further investments planned" for .pst files in new Outlook.
What people run into
A buyer of Office Home 2024, which has no classic Outlook, couldn't select her transferred outlook.pst and was told Outlook data files need a Microsoft 365 subscription:
"I have many folders with saved emails going back years, and I do NOT want them on OneDrive. I want them on my computer!"
The answer she got: "New Outlook only has limited support for .PST files at this time." (Microsoft Q&A)
Another user asked for full .pst support:
"I like the new interface, I'm not willing to leave my pst behind."
The accepted answer: no date has been announced for full support. (Microsoft Q&A)
What happens in March 2027
Microsoft plans an opt-out phase that moves classic Outlook users to new Outlook starting in March 2027. Classic Outlook stays installable during that phase, but users may be switched over by default (The Register, Microsoft message center MC949965, via kurtsh). Dates like this have moved before, so check Microsoft's current guidance for your organisation.
How to keep your old mail safe
- Find your .pst files. Classic Outlook usually keeps them in Documents\Outlook Files. Copy them somewhere backed up.
- Check they open. Open each one in classic Outlook, or in a viewer that doesn't need Outlook, while you can.
- Convert what matters into open formats: PDF for records, .eml for single messages, .mbox for whole folders you want in Thunderbird or Apple Mail.
PST Rescue does steps 2 and 3 on Windows without Outlook. Reading, searching and saving single messages are free; exporting whole folders is free for the first 50 messages, then $29 once. Everything stays on your PC.
Get PST Rescue from Microsoft Windows 10 and 11
Questions
Will my .pst files be deleted when I switch to new Outlook?
No. Switching apps doesn't delete files on your disk. The problem is opening them afterwards.
Can I import a .pst into my Outlook.com or Microsoft 365 mailbox?
Classic Outlook can, by opening the .pst and dragging folders into the mailbox. That puts your mail in the cloud, which some people don't want.
Can new Outlook open .eml files?
Yes. Exporting important messages as .eml gives you files new Outlook, Thunderbird and Apple Mail can all open.
More: How to open a .pst file without Outlook · PST to MBOX for Thunderbird