The current software for the SunEye and PVA-600 is compatible with Windows 8. SunEye users: If you have upgraded your computer to Windows 8 and had our SunEye desktop companion previously installed, you will need to reinstall the Windows Mobile Device Center from Microsoft (RAPI.dll error). There are links to the site where you can download this program from our software downloads page: www.solmetric.com/support-downloads.html Be sure to select the 32 or 64 bit version appropriate to your system. If you are installing the software for the first time on Windows 8, be sure to use version 4.62 or later. The latest version is available from this page: www.solmetric.com/support-downloads.html It may be necessary to plug the SunEye in BEFORE starting the software installation. This should cause Windows to automatically install a driver and the connectivity software (Windows Mobile Device Center, aka WMDC). This may take a few minutes. After WMDC is installed if it does not open automatically, launch it from the applications screen in Windows 8 and it should display a license agreement and then connect to the SunEye. DO NOT SETUP WMDC. Once you have a connection you should start or restart the SunEye software installation. PVA-600 users: No additional steps are required after upgrading your OS.