T-Mobile connection manager (ZTE modem) reinstall: “An earlier Speedmanager plus/ByteMobile Client installation exists on the system. This version must be uninstalled and OS restarted!”

When reinstalling the software T-Mobile “web’n’walk” :

“An older manager Speed plus / Byte Mobile Client Installation (SDK) was found.  The software must be uninstalled and the computer rebooted.”

Open regedit, search for “ByteMobile”, delete every hit.

Run the setup again, reboot computer…