All of a sudden it seems I have this problem too. I get error (1,105(0x103F7)) doing scheduled backup to a network drive, but only from one computer. Other computer works fine. I have TI 9 home. Both computers running XP PRO SP2. I haven't upgraded TI for a while but windows is always doing it so I suspect MS has done something because this problem just started. I think I fixed it. I saw somewhere a suggestion to use full UNC to specify network drive (\\server\ etc). I could not make this work by editing an existing scheduled task. I had to delete it and then enter it again using UNC. I have to say, I have solved many network addressing issues in general by using UNC instead of referring to the mapped drive. There are many threads with this same problem, but I am only responding here.