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April 30, 2013 /News, Views & Updates /

Workaround for Safari 5.1.9 incompatibility with Adobe Reader and Adobe Acrobat

Mac OS has been one of a very widely used platform by Adobe customers. But recently, with a Safari upgrade the compatibility of Adobe Reader and Adobe Acrobat applications to open PDFs inside browser has again come to a hold.

As you install an Adobe Reader and Adobe Acrobat application on a Mac machine, the installer additionally installs a NAPI plugin inside Library -> Internet Plugins Folder, so that Mac users can open PDFs inside Safari using Adobe Reader/Acrobat app seamlessly (instead of using the conventional Preview which only supports a small set of PDFs).

But For Mac Snow Leopard users, the upgrade of Safari to 5.1.9 has proven fatal. Till Safari 5.1.8, users will be able to still open PDFs inside Safari without any issues. But post upgrading Safari to 5.1.9, Adobe Reader do not opens PDFs inside Safari.

As of now many users have reported this issue on Apple Blogs:

Some users have reported this issue via Bug to Apple as well (rdar://13694491)

To resolve the issue, I hereby give our Adobe users a quick workaround:-

Basically, the earlier versions of Safari used to have an entry in the for WebKitOmitPDFSupport which now do not exist anymore. So we just go and add it.

To add the entry:

1.)    Go to Library -> Preferences

2.)    Open “” in Property List Editor or any Text Editor like TextWrangler.

3.)    Add a new key with the name “WebKitOmitPDFSupport” of type Boolean and define its value as True (checked). i.e.:


4.)    Save the plist.

5.)    Restart Safari.

Property List Editor Snapshot

After applying the above workaround, users will be able to open PDFs inside Safari again. Note that, in case if you don’t have Adobe Reader / Adobe Acrobat installed on your Mac, then the above workaround will simply download the PDF onto your system.

Just for reference, Adobe fixed the same issue earlier in 2011 for Safari 5.1.0 :

Categories: News, Views & Updates


  • By Gary Cosimini - 5:51 AM on May 1, 2013   Reply

    I found the alternative Apple Blogs suggestion, using Terminal, is slightly simpler than editing a plist:

    "You can also run this command in Terminal:

    defaults write WebKitOmitPDFSupport YES

    If Adobe Reader is installed: this will load all PDFs in Safari using Adobe Reader
    If Adobe Reader is NOT installed: visiting a site with PDFs will end up downloading the PDFs to your Downloads folder."

  • By Ted Swann - 3:31 PM on May 1, 2013   Reply

    FYI, it’s not “MAC” in capital letters; it’s “Mac” (short for Macintosh).


    • By joiemikitson - 7:39 AM on May 6, 2013   Reply

      Good catch, Ted. We will adjust the article to include that. Glad to have such dedicated Mac fans reading our blogs!

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