Ventura 13.1 opens PDF randomly with differently applications

Thanks for all you help.

Your suggestions reminded me a long time ago I encountered a strange problem and it was fixed by clearing system cache as suggested by Apple Support. I tried booting into Safe Mode a couple of times using instructions from Apple Start up your Mac in safe mode - Apple Support. But the problem remained.

When I double clicked on a PDF file, most of the time, it was opened in Acrobat. If I right clicked on the file and selected "Open With" and then the default application (first entry in the popup menu, which is PDF Expert), it opened with PDF Expert. If I selected "Other..." on the second popup menu and then "PDF Expert.app" in the application folder, it showed an error message.

When I clicked Open on the message, the file was opened in "PDF Expert". If I tried other files, they still opened in Acrobat.

I tried to override application security on "PDF Expert.app" by holding down <Ctrl> while clicking on the application according to this article https://www.lifewire.com/fix-developer-cannot-be-verified-error-5183898. It did not change the behavior. Note that I used PDF Expert for many years and I know it is safe. The last update of the app happened in July 2022, and I opened the app dozens of time every day. The problem was caused by the latest Ventura 13.1 update.

After all the experiments failed, I went back to P. Philips' suggestion. On the Info page, I changed "Open With" to Acrobat. Then I changed it back to "PDF Expert". It worked. Now all PDF files are opened with the default app.

Since there were quite a few things I tried, I cannot tell which step(s) fixed the problem. I am recording the steps here hoping it will help someone else in case they encounter similar problem.

I tied that already. It did not change the behavior. The default icon for PDF file in Finder was still Acrobat. Some files were still opened with Acrobat. This is very strange. I never had such an obvious mess up in MacOS before.

I agree with you that having more than one PDF viewer is generally not necessary. But in my case, I need both.

I have been using Adobe Acrobat and Adobe Reader (or whatever it is call at the moment) since the beginning. A few years ago, I finally had enough of the slow loading of the application and ever evolving user interface. I purchased PDF Expert mainly because of its fast loading and simple user interface that was well designed. I stopped installing Adobe Reader on my computers until an organization that I worked with had problem reading files saved by PDF Expert. They did not have the budget to upgrade to a newer version of Adobe Acrobat which fixes the problem. So I had to fall back to open a PDF file saved by PDF Expert in Acrobat Reader, and save it again before sending the file.

Anyway, thanks for your suggestion, it saved my day.