Apparently there are two different PST file formats - an older one using ANSI encoding which has a limit of 1.9GB and a newer one using Unicode encoding which has the 50GB limit. Perhaps
yellowtriumph's PST is using ANSI having come from an earlier Outlook version?
https://support.microsoft.com/en-us/...iles-in-outloo
Here's how to tell which format you have:
https://www.slipstick.com/outlook/co...nicode-format/
Methods for converting ANSI to Unicode:
Convert an ANSI PST to a Unicode PST