Yesterday morning we resolved a problem that prevented Flash Player installations from completing for some of our Macintosh users. Please delete any previously downloaded Flash Player installer, clear the browser cache and either:
Download the installer again from https://get.adobe.com/flashplayer, OR
Download the stand-alone installer posted at the bottom of the http://helpx.adobe.com/flash-player/kb/installation-problems-flash-player-mac.html in the ‘Still having problems’ section.
If the issue persists, please provide a screenshot of the installation window exhibiting the behaviour (seeThe specified item was not found. for instructions)