This error may mean that the operating system on which you are attempting to install Grapher is not supported, or that the installation EXE file was not fully downloaded. The current version of Grapher requires Windows Vista, 7, 8 (excluding RT), 10 or higher. Additionally, sometimes company firewalls or virus checkers prevent the last few bytes of a file from being downloaded. If you can, try disabling the firewall or virus checker and then downloading the file again.
If that does not help, please right click over the file you downloaded and click Properties. Note the file size of the file you downloaded (in bytes) and email this information along with the name of the file you downloaded to firstname.lastname@example.org.
Updated January 25, 2017