For anyone interested, the problem is certainly linked, as Elmer suggests, to those of us who "tinker". However, in this particular case, I object to Microsoft's interpretation of the word. It is caused by the renaimg of file/folders, which do not follow the 8.3 convention. For instance, if you manipulate legacy programs, throught the officially offered Compatibility facility, thos programs, through their XP or other legacy facility, can put a .tild (that squiggly worm ¨), into a file or folder name, which windows 7 cannot accept. After four or five years, time MS sorted it!