Installing & Launching - Windows Defender Security Center.
In addition to any installed virus protection apps, Windows 10 installs with a Windows Defender Security Center that has virus, threat, account, firewall, and network protection. So even if you have temporarily disabled your virus protection app, the Security Center could be blocking the installation or launching of ExtendSim. You may need to change the settings or set the ExtendSim installer to be excluded in the Windows Defender Security Center. Be especially aware of those settings if you are attempting to install ExtendSim on virtual machines using Windows 10.