In the ProCall client, some tabs are not displayed, e.g. favorites or planned calls. The problem usually affects only isolated clients and typically only one user on the PC.
This error screen appears after installation of the client (also updates).
A more precise cause of the error is not known.
Please perform a clean uninstall of the ProCall client. For this purpose, all entries and files in the registry and the AppData directory must also be removed.
For this procedure, it is recommended to use applications which enable a clean deinstallation such as "Geek Uninstaller".
Please note that these third-party applications also access the registry! Therefore, make a backup of your system in any case!