backups being stored as Adobe PDF files

Question

Started cleaning up old backups before starting full image backup to external hard drive.  I do a weekly b/u to thumb drive for years, no problem.  I managed to delete ALL my usable backups and had to restore from recycle bin!  Then noticed that most of old backups show as Adobe PDF files.  Never noticed this before.  Over the years have had to restore from backups, which worked.  Concerned that new backups may be saved as PDFs before I realize it.  Any ideas?  Thanks.

Windows 11; Quicken Deluxe, R65.17

goofiness · Answer

Thanks for your comments.  I did some more research and found the simple solution.  Right click any one of the .PDF files, then just look at Opens With, and change from Adobe PDF to Quicken QDF.  That changed all of them back to QDF files.

Those PDF files wouldn't open with Adobe or Quicken, and I did not try changing the extension.  No idea how the Open With got changed.  Learned something today.  Now I can get back to deleting all my old weekly backups.

q_lurker · Answer

Have you looked at the actual file name extension?  Commonly the app showing the files does not show the extension and instead list the program it has associated to the file extension.  The extension-program association may be wrong.  Off the top, I don’t recall the process for changing that association.

NotACPA · Answer

Have you tried actually opening these files with a PDF viewer?  What are the files named?

Because, what you're describing simply isn't possible.  Q's backup process merely creates a copy of the existing file, and doesn't invoke a PDF writer to create a PDF file.

Have you tried changing the extension of one of these files to QDF (the proper extension) and opening it?  Because the most likely, to my thinking, explanation is that they're simply mis-named.