installation failed - Adobe Flash Player vers 23. Mac

Hi,When I try to update Adobe Flash Player, the installation begins but at the ebd it says:

Installation failed. Click `Finish´for further as...

I am using a MacBook pro late 2013, intel Core i7 with El Capitan.

I have closed all windows

I can see the existing Flash Player is a vers 21.

I hope you can help me 🙂

Best

Mark