The path information may have changed unintentionally, then set it correctly again.

The backup copies have the file extension .iwzip, possibly search with Windows Explorer to find out the path.

If it is a program error, then reinstall WebSiteX5. To do this, click on the user name at the top right and click on "My Profile". Here you will find the program for downloading under "Download" and the program for installation under "License key".

If all fails, maybe the moderators have some tips, otherwise wait for the Incomedia employees, but they won't be online again until Friday because there's a day of vacation on Thursday.

Have you changed the project directory in the settings (gear symbol on the left side). Here you have to select the directory in which your projects are saved.

You can search for your projects on your hard drive using Windows Explorer. Mark "This PC" at the top left of the folder window, then enter *.iwprj2 in the search field at the top right and let it search... It may take a while. The folder above the directory(s) in which the project.iwprj2 files are located is the projects directory. You enter this in the settings. You can find this on the home page, before you have loaded a project, at the bottom left under Settings (gear symbol).