On loading the background map, map tiles are shown on the wrong position and from different zoom levels.
This can happen in the interaction with the firewall used in the network. Following workarounds are possible: - Set the option 'Automatically detect settings': Internet Explorer -> Configuration -> Internet options -> Connections -> LAN settings - Rename the file c:\Program Files\PTV Vision\PTV Visum 2020\Exe\HttpLib.NET64.dll tentatively and start PTV Visum again. (If this helps, you will need to repeat this after each Service pack.) - Turn off any firewall 'Deep scan' function. (Ask your IT for support.) - If all these workaround do not help, and if the background map can be dispensed: Use an adapted version of the STD.GPA without displaying the background map and save it as: c:\Users\%USERNAME%\AppData\Roaming\PTV Vision\PTV Visum 2020\;12.50