Preview doesn't read PDFs?

Hi

My Preview app doesn't read PDFs anymore but can read images and text. I have updated Safari to the latest Adobe software and can read the latest PDFs there but when I save and OPEN WITH Preview I get

Please wait...

If this message is not eventually replaced by the proper contents of the document, your PDF viewer may not be able to display this type of document.

I have perfomed first aid using Disk Utility with no effect.

I have read numerous threads but none have had a fix.

Any clues what do to next?

Many Thanks in advance

Brian