How to set Adobe DC PDF reader as default for ALL pdfs without having to open security preferences every time I recently switched to Mac from Ubuntu and I'm trying to set Adobe Acrobat Reader DC as the default pdf reader for all pdfs. I assumed this would be straightforward, however, when I download a new pdf, it defaults to Preview because if I try to set Adobe DC as default I get the following message 


  something.pdf can't be opened because it is from an unidentified developer. Your security preferences allow installation of only apps from the App Store and identified developers.


Then I have to go to security preferences and explicitly approve Adobe Reader. This is incredibly annoying because Preview doesn't support tabs and I tend to have several pdfs open at any given time and don't want to open each in a separate window.

Is there a way to change the security preferences such that all opening all pdfs with Adobe reader is allowed by default?

I'm on MacOS Mojave.
Select a pdf file in Finder and click the Command-I keys to display the Get Info panel. Click on the lock icon at bottom of the panel and enter your password. Then  click on the "Open With" pull down and select Adobe DC and click the "change all" button. This sets Adobe as the default for pdf files.