Hi. I know this question has already been asked. But I have tried the solutions provided and they haven't worked for me.
I am working with Adobe Creative Suite 4, Design Standard, for Mac OS. My OS is 10.6.8. The specific program is Adobe Acrobat 9 Pro, version 9.0.0.
I edited my document with redaction tools. When I tried to save it, it says: "The document could not be saved. The file may be read-only, or another user may have it open. Please save the document with a different name or in a different folder." I have tried saving with a different name and different folder and it still doesn't save.
I also get a Mac error message that says: "The document could not be saved. There was a Macintosh system error (-51)." Now that I've tried saving so many times, I only get this Mac error, and not the Adobe error.
For some users, the problem was solved by turning off "protected mode," but this feature was introduced with Acrobat X.
First of all, install all of the available updates for your version.
You can get them from here: ftp://ftp.adobe.com/pub/adobe/acrobat/mac/9.x/
You need to download and install them all in sequential order.
Thanks try67 -- it worked after installing just the first update! There were many updates, as you know, and I have to finish the project immediately so I decided to just try it again after the first one. I'll bear in mind for the future that updates might solve problems.