Bug reports without an attached log file are usually useless.
Thank You, was the right hint...
Re: Site import not aviable
The option is disabled when WinSCP cannot find any PuTTY/FileZilla sessions.
WinSCP looks for FileZilla sessions in C:\Users\username\AppData\Roaming\FileZilla\sitemanager.xml.
Do you have them stored elsewhere?
Site import not aviable
In the version 554 there ist no Siteimport active. After installing the Programm the Field "Site import" under tools is dead. No import possible... (Tried to import a FileZilla profile).