mac want open pdf

do you have adobe acrobat installed?

or any pdf viewer?

It is not the Mac, it is Safari and the browser internet plug-in from Adobe. You most likely are not having the problem when you use the Firefox browser. I found this answer in another dialogue chain and it will fix the Safari browser issue.

"In Finder Go to: Macintosh HD/Library/Internet Plug-Ins and look for "AdobePDFViewerNPAPI.plugin" and move it to Disabled Plug-ins Folder (if you want to keep it). You will have to remove this file from the Internet Plug-Ins folder altogether. (I put mine in the trash)

In the ../Internet Plug-Ins folder you should also have the file called "AdobePDFViewer.plugin" leave this. In my case this was the older plug-in dated June 2011. This works. The plug that I removed was part of the Adobe updated I downloaded yesterday which was the problem (Thanks Adobe)

Relauch Safari and you should be able to save the PDF files."

Again, I found these instructions and they work perfectly. I moved my AdobePDFViewerNPAPI.plugin to the Trash as well. Now I can view my pdf once again.