i installed version 4.2... of mkvtoolnix. I then copied the code aboved into notebook, removed the three lines that state 'REM' and saved it as a *.cmd..., placed the file into the mkvtoolnix folder. placed my 'corrupt mkv' (badmkv) into the folder aswell and ran the cmd file. A dos box appeared for like 1 second. i did not see any changes happen to the badmkv. it still does not work, however if i run the program mkvtoolnix (mmk.exe i think it's called) and add the badmkv and go through all the settings and 'remux' it, it works... my question is why does my .cmd file not work? even dragging the badmkv onto the .exe as stated above, i get a 1 second dos window...but anyways at least i can get it working even if i must do it the long way. thanks for the help guys. i just revived some awesome episodes i had missed. windows xp with sp2.