It appears that the Path to the PDFs that the database maintains has been broken.
This could happen, for example, if the database file and the PDFs are now on different volumes.
Suggestion; Inspect the Info panel Path field for one of the PDFs that now displays as a small image. Where did the database expect to find the PDF file? Where is the PDF file in fact?
No, Bill, the database file and PDFs have never been on different volumes. The database file and embedded/indexed PDFs have been located on an external RAID since 2005. Good thing. Because I have been through over four internal hard drive losses since then.
I had this problem when I upgraded to DTPO, and someone from DT (not you) wrote that it a common problem and was resolvable by checking or unchecking something in the Prefs.
The PDFs look as if I have turned my screen to 800 resolution.
Sorry, I was thinking about another type of problem when Indexed PDFs have a broken Path. One then sees only a low-res image of the first page.
By “embedded” PDFs do you mean PDF files dragged & dropped into a rich text file? One can set DT Preferences > Editing to display attached PDFs. The PDF file then becomes readable in the body of the rich text note. If one double-clicks anywhere in the PDF image the file will open under its default application, in my case Preview.
If that’s the case, what happens if, while viewing such a document, you press Control-Command-Down Arrow, perhaps several times. Each time that keystroke is pressed the viewed size of the note contents become smaller. DT remembers the current setting. At high magnification a PDF scanned at a low resolution will appear blocky.
A downside of such embedded or attached PDFs is that their content is not indexed nor is the PDF text searchable in the Search window.
Do you think I could replace the pref file from a drive where I know DTPO worked properly into the library on the drive I’m working from now? Would a pref file be all I have to change?