On Windows, it is impossible to store files with a ? in the file name, similarly on Linux, a file with slashes in its name cannot be saved. People use illegal characters in their file systems every now and then. Mostly I could work around this by switching to Linux or Windows, but it is annoying.

LW shows a message that the file could not be stored and goes to 100% immediately. It recognizes the problem, as it seems.

Do you think you could add a feature to rename files before storing them in order to avoid this problem?