N/APosted on - 03/02/2012
I tried opening a PDF document which showed me the error message, for which I have deleted the application (Acrobat Reader 5.1) long ago.
The error doesn’t contain any useful information on how to open the file with other application although I had newer versions of that application (Acrobat Reader 6).
The operation could not be completed.
An unexpected error occurred (error code – 10660).
Opening PDF Document issues in Acrobat Reader 5.1
I wish there was more information regarding the error instead of the generic Mac OS error pop-up.
From what I could understand, you are trying to open a PDF file using Adobe Reader but the error window pops up. Adobe Reader 5.1 and Adobe Reader 6 are both very outdated versions of the popular PDF reader. My suggestion is to uninstall you current version of Adobe Reader and download the latest version (currently Adobe Reader X) for your version of Mac OS from here:
If you are using Mac OS X, just use Preview – the free built-in PDF reader. It's better than Adobe Reader and does more for free.