I completely uninstalled the Teamviewer, run 3 antiviruses and re-installed it, and checked the antivirus and everything and could not find anything that could interfere or impede it to open. I have learned that other many customers are having the same problem. I have the free version and I use Windows 10 Professional (up to date on everything). I downloaded the PORTABLE version and it is working but I would prefer to have TeamViewer installed. Any suggestions on how to fix this issue?