Preview view in Explorer Files

Hi

All day every day I use the preview option in Explorer Files.  In the past I was able to move from document to document - PDF, Word, Excel and all would preview no dramas.  Now I am getting a preview of 1-2 before I need to close down and restart Explorer for the preview to work.

I have spent time and $$ with my IT guy only to be told this is a new feature Microsoft introduced - allowing only a certain amount to be previewed.

This is truly slowing my productivity.  How can I stop this happening or when will Microsoft fix this issue.  I don't know if anyone else is having this issue