Apple’s Safari comes with lightning-fast built-in PDF viewing support. If you ever make the mistake of installing Adobe’s Acrobat software (in free or paid forms) then you’ll find that Adobe has installed a bloated, slow, beachballing, almost unusable plug-in of its own which overrides the excellent built-in one.
A quick Google search on the topic reveals a large number of links on how to get back the superior behaviour:
The best information appears to be in this article:
When I fired up Adobe Acrobat and went to the "Internet" section of the preferences I was dismayed to see that the checkbox for disabling the plug-in was ghosted out. I thought that this was likely because I was running from an unprivileged non-administrator account as is my custom. So I fired up the Terminal and launched Acrobat again using sudo; I was now able to disable the checkbox.
But when I fired up Safari I saw that it continued to use the unwanted plug-in and on launching Acrobat I saw that the checkbox was again ghosted and checked.
I tried temporarily granting administrator privileges to my daily use account, but the checkbox was still ghosted.
Some of the hints out there suggest merely deleting the plugin itself (at
/Library/Internet Plug-Ins/AdobePDFViewer.plugin) but this Adobe article notes:
If the AdobePDFViewer files are deleted, then they will be self-healed after you start Acrobat again after the files were deleted. You can also fix Safari manually by choosing Help > Repair Acrobat Installation.
In other words, if you fix the infection, Adobe is likely to reinfect your system all over again under the guise of this unwanted "self-healing".
The solution was to manually move the plug-in into
/Library/Internet Plug-Ins/Disabled Plug-Ins/. From that point on, Safari fell back to the built-in support, the Acrobat preferences showed the checkbox as unchecked, and the "self-healing" feature did not kick in and "fix" my installation.
Even this solution, however, wasn’t straight forward. Even from my administrator account I couldn’t drag or even copy the plug-in into the
Disabled Plug-Ins folder. It turns out that the folder was owned by
root but its group was another user (my other administrator account). The only item in the folder was a plug-in named
Windows Media Plugin (surprise, surprise). I believe the folder should have been created with user:group
root:admin. Let’s blame Microsoft, shall we?
So I changed the group of the folder to
admin and was then able to move the unwanted plug-in inside using the Finder after authenticating (actually this consisted of a copy followed by a deletion of the old version, due to the way the permissions system interacts with the Finder).