Can't do a word search in one pdf file

I'm using Adobe Acrobat 2019.012.20040.  OS is Windows 10 Pro.  I have a pdf file that does not perform a word search.  The message says that the search has been completed and nothing was found.  (I tried using very common words such as "the")  This same file on my wife's computer also does not perform a word search.  Other pdf files on my computer that I've tried will do the search.  Based on something I read, I disabled "fast find" and clicked on "Purge Cache".  I also tried deleting Adobe Acrobat and reinstalling a fresh copy.  I couldn't reinstall because I received a message saying the version I was trying to install was not as recent as the version on my computer.  I checked again but didn't find Adobe Acrobat since I had deleted it.  At least wanting to have a partially working Adobe Acobat, I did a restore to prior to my deletion of Adobe Acrobat.

A recommendation to fix this issue will be much appreciated!