FTP error „home directory inaccessible“ after server reboot

One reason for the FTP error message „home directory inaccessible“ is the usage of two sites with the same host header in IIS. (for FTP access) Usually it isn’t possible to add two sites with the same host header and the same IP. But it is possible to stop one HTTP/FTP site with the host header www. mydomain.com and create/start a new site with the domain www. mydomain.com. The IIS remember which HTTP site is on or off. But it looks like it doesn’t remember which FTP site is on after restarting the server/IIS.