In this guide, we will show you a nifty workaround to fix the Unidentified Developer error when changing the default PDF viewer from Adobe to Preview. By default, you can open your PDF files via the built-in Preview app. In most cases, it tends to checkmark most of our prerequisites, however, if you are looking for advanced functionalities, then you might opt for the offering from Adobe.
However, if you ever wish to revert to the stock Preview app and make it the default app for PDF, then it might prove to be a tough nut to crack. We found out that if currently, we had Adobe [or any other app belonging to this domain] set as our default PDF reader and then we tried to make Preview the default PDF reader app once again, then it would not be able to open that file, instead, we will be greeted with the Unidentified Developer error.
The complete error message reads out: “File cannot be opened because it is from an unidentified developer“. This is really quite strange because the file that we are dealing with was present on our Mac for ages and never did it raise any concerns whatsoever. Moreover, if you switch the default PDF reader app back to Adobe, then it will once again open the app without any issues. So why is this happening and is there a fix? Let’s find out.
Change default PDF from Adobe to Preview: Unidentified Developer Fix
The reason behind this issue could be the quarantine flags on the files. They are a small item of metadata and were initially used for apps and executable code, to determine which should be passed to Gatekeeper to undergo tests. However, over the course of time, they were also embedded into files.
As far as the rectification measures as concerned, you could take the help of third-party apps like Pratique which would set the status of quarantine flags to “off” for that concerned document, and then you’ll have no issues in accessing them. So try out this tweak and let us know in the comments if it fixes the Unidentified Developer error when changing the default PDF viewer from Adobe to Preview.