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.

I want to add my name to the chorus lamenting the lack of PST files in the new Outlook.

I and my company were beta testers for the original versions of both Exchange and the Outlook client. I have been archiving my emails annually to PST files for the last 26 years. I make regular use of these files, especially for the more recent years. These PST files are both useful and efficient to me. The idea of importing those files into an OST boggles my mind.

Gotta have PST files. Plus there were a bunch of other irritating shortcomings or changes that I didn't bother to list since I bailed out within 30 seconds when I realized that PST files were not supported.

According to the M365 roadmap - Microsoft 365 Roadmap | Microsoft 365

I am an IT Admin in a K-12 public school that has the A1 licensing model. Since we are state funded, we have to comply Open Records Requests or Public Information Requests. In the Microsoft Compliance Portal, we can easily create Content Searches and retrieve the search results, but to export those, our options are as individual messages or PST files. Sometimes those results are thousands of message, so individual messages isn't an option. We need the capability to open the PST file and the new version of Outlook does not have that capability. When should we expect this to be added to the New Outlook?

This is another change by Microsoft that disregards long standing users. To cut off access to email accounts unless users upgrade to a newer, limited product, without being able to use their existing files, is foolish, non productive, and shows a disregard for longstanding customers.

Wow ! It is a big blow for the reputation of Microsoft ! I had difficulties to believe that.