Hi,
I have a single use license of ArcGIS Desktop Advanced 10.3.1 running on a 64 bit Windows 10 Pro. I didn't have any issues with the software so far until I tried to create a Python Add-In Toolbar... After I successfully installed the new created toolbar, neither ArcMap, ArcCatalog or ArcScene won't start at all. When I try to open one of the applications the initial small window appears with Initializing License... and it gets stuck like this. I have to stop the application from the task manager to close it. I uninstalled the software, deleting all the remaining files