How can I mount a data file (pst) in new outlook. In the classic version this is doable through the File menu which is not available in new outlook.

That suggests to me that there may be an issue with your M365 installation, you might consider repairing it, Start > Settings > Apps, find Microsoft 365 Apps in the list, click it, click Modify, and select either Quick or Online Repair. In my experience, Online Repair is more thorough. If the issue persists, please follow up here so we can dig deeper. If you can capture that random message in a screenshot, please consider posting it so we can have a look at it. Thanks!

I've just built a new machine for home and managed to install Classic without any issue and have relinked my old PSTs. Be good to keep up to date, but Microsoft clearly don't want to play the game and support their customers, just increase our annual subscriptions for lower quality products. (28% increase for me this year)

Import from an External PST File:

• Click on File in the Outlook menu bar.
• Select Open & Export > Import/Export.
• Choose Import from another program or file and click Next.
• Select Outlook Data File (.pst) and click Next.
• Browse to the location of your PST file and select it.
• If the PST file has a password, enter it and click OK.

Where is "FILE"? I don't seem to have that option after switching to the new Outlook. I have several different offline data-files that I used in the Old Outlook that did not come through when I switched to the new one. Only my main domain mailboxes came over. This is a detriment and makes using the new Outlook completely impractical. Yet in attempting to switch back to the old Outlook, I am somehow not receiving new emails and just keep getting a "Not Responding" lag. It's left me completely inoperable for work tasks for 6 hours thus far today.

(It says it inserted an image I'm trying to share of my menu bar - but I don't see it on my end, so going to hit submit and hope for the best).

Can anyone please answer this question.... Where is FILE in the new Outlook menu bar??

I cannot even do step one to access my previous Outlook Data Files (pst).

Also my previous old Outlook has just completely disappeared!!!

It's not there. Many of the 'answers' here assume Outlook 365, NOT the desktop version, which is more than a little annoying. AFAIK this very basic, IMO, function is not available in the new/current Outlook desktop. Based on the history of this thread, which goes back over a year, I seriously doubt MS intends to fix it.

Thank you for your reply.

I did end up finding a response with a link to download a standalone version of Classic Outlook and this worked!

I could again access all my email and back to the Outlook I know and prefer.

I can't understand how the Classic Outlook literally disappeared after I installed Microsoft 365??

Thank you for answering my question: appreciate!