trouble re-saving modified PDF files

Has anyone had any trouble re-saving PDF files after making modifications to it (highlights, add comments, etc) - and solved the problem????

After I updated my Adobe Acrobat to the latest version, everytime I modify a PDF file, when I click SAVE, it does not do that !! Instead it makes a TMP file which I cannot open later. The only way I can save my modified PDF file is to click again SAVE and over-write the original file.

It is SOOOOO ANNOYING! Why the heck Adobe does that??? Please help. Thanks in advance!