Recently, I tried something that had always worked before. This time, it didn't.
Using Safari, I clicked a link to a PDF file. After the PDF opened in a browser window, I selected the Save As... command from Safari's File menu. So far, so good. Next, I double-clicked the saved file sitting on my Mac's desktop. Normally, this opens the file in Preview. This time, however, I was greeted with this error.
A similar message appeared if I tried to open the file in Adobe Reader, rather than in Preview. I next tried saving the file from Firefox instead of Safari. It made no difference.
Returning to Safari, I selected the Print command. From the Print dialog, I selected to save the file as a PDF. This too failed to save a viable copy.
I finally discovered a route to success. If I clicked my trackpad when the pointer was over a PDF page in Safari, a toolbar overlay appeared. One icon in the toolbar was a floppy disk (really!). Clicking this icon saved a copy of the file that (at last!) opened in Preview with no errors.
The problem was not restricted to a particular PDF file saved from the web. It happened with any one I now attempted to save. PDFs that did not originate from a web page continued to open just fine.
I wasn't certain why the problem had first popped up when it did, nor why one particular method of saving worked while other similar ones did not. However, I was fairly certain as to the culprit: I suspected the Adobe .plugin files used for PDF viewing. Two such files resided in my /Library/Internet Plug-Ins folder: AdobePDFViewer.plugin and AdobePDFViewerNPAPI.plugin. If I removed this pair from the this folder, Safari reverted to its built-in (not Adobe-based) method of viewing PDF files. After I did this, problems with saving PDFs from Safari vanished.
To be clear, removing these plug-ins did not eradicate problems with previously saved files. It just prevented symptoms going forward.
My next step was to check if there was a more recent version of these plug-in files that fixed this problem. At first, the answer appeared to be no. As I knew these files get installed as part of Adobe Reader, I launched the app and selected Check for Updates. It said I was already using the latest version (10.1.5).
Not ready to give up, I also checked Adobe's website. Contradicting the Reader app, the site listed a newer (11.0.01) version as available. After I updated to this newer version, the PDF saving bug was gone!
Unfortunately, the update introduced a new bug. Now, when I select to save a PDF file from Safari, I have to save twice. At the second instance, I am asked if I want to replace the file I just created a moment before. While a minor irritation, it's been enough to get me thinking that I would be better off giving up on Adobe's plug-ins altogether.
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