When viewing some PDFs in Safari on a M1 Mac mini (running macOS 11.4), Safari shows a "Blocked Plug-In" page and the PDF is not shown.
Following resolution steps have been attempted:
- An existing Adobe Acrobat Reader installation was uninstalled completely from the System using App Cleaner
- Files in /Library/Internet Plug-Ins/ or the corresponding user libraries were removed
- The exstensions Page in the Safari preferences was checked, no active plugins were listed
- All Website data has been deleted
- The computer has been restarted after attempting each of the listed resolution steps.
What could be causing this blocked plugin message to appear only for some PDFs and what could be the solution to this issue?