Hi, I have recently upgraded my computer to Windows 8.1 Pro x64 and after this upgrade I can't run Athena and Artemis. The problem symptoms are: 1- If I use Demeter version 0.9.13, Athena opens but when I try to open previously saved file, Athena simply crashes without showing any error. Artemis also shows similar behavior. 2- By using latest build Demeter 0.9.19, Athena behavior is slightly different it opens the files and show the plot. But pressing the E,k,R buttons does not change the plot. Artemis still crashes by opening any project file without any error. I have tried following things, installed in compatibility mode of Windows7. Athena worked fine only once after installing in compatibility mode. Installed in different drives but situations remains the same. Tried to "run as Admin" but no improvement. Installed Demeter on three different computers running Windows 8.1 x64 but similar behavior is received. Kindly suggest me some work around because I have to use Demeter on almost daily basis. I have attached log file obtained from Demeter 0.9.13 running under Window 8.1 x64. Thanks, Shoaib Muhammad Department of Energy Science Sungkyunkwan University South Korea