Tried all the stuff on Flash Player in Adobe forums with little success. This is occurring on lots of different Macs and assorted Mac OS’s. The only way I managed to fix was to delete all copies of Flash, Flash installer. flash player.dmgs and any other exclusively Flash support files. Empty the bin & restart the Mac.
Then go to https://get.adobe.com/flashplayer/ for a brand new copy to install from Adobe. BEWARE! Make sure you back up completely before doing this so you can go back and retrieve any files you mistakenly delete.
As always if you are not confident in resolving this issue we can do it for you. Appel repair & upgrade all Apple Macs – iPhones & iPads too.