Some PDFs only open with File>Open
I am using Acrobat Professional 7 on a Win 10 system. I know this is not supported, but other than the PDF printer not being installed, everything seems to be working ok.
Today I started to notice that some PDFs would not open when I double click the file name (or right click and select Open with), but they would open fine from within Acrobat (File>Open).
I checked Windows file associations, and all is well there.
I also tried an Acrobat repair (Help>Detect and Repair) followed by a reboot. That cleared things up for a while, but then it stopped working again.
Any ideas?