Click the drop-down menu at the top-right of your screenshot - Restore Column Order

Hi Christ1, Thank you for this, but clicking on "Restore Column Order" makes no difference, still only the 3 columns, even when in full-screen width format. Nor can I find any files with the 'subject' field that I could apply as a default to all the rest. However, I've just come across a substantial discussion on same problem (mid-2020) - and it seems this is a common, long-standing issue.

Solution! 1 Click on 'Restore Column Order'. 2 Look at headings. Between paper clip and double-dot columns is the hidden 'Subject' column (not sure how I found this). Widen this by dragging heading divider (as in Excel). 3 At right hand end in headings row, click on small icon 'Select Columns to Display', then on 'Apply Columns to' at foot of list. 4 Drop down boxes will appear appear progressively. Select 'Folder and its children' not just 'Folder'. The correct format will then apply to any new sub-folders added later. 5 Arrive at lowest folder level. 5a If no sub-folders, click on folder name, then OK in 'Apply Changes?' box. 5b If sub-folders exist, click on the folder name only, at top of the box that appears, then OK in 'Apply Changes?' box. 6 Repeat from step (3), until all folders and sub-folders show correct format with Subject. There may be an easier way (for example if all folders could be selected for action) and if so, I would like to know. I hope this helps.