Then I misunderstood how it works, but the change would be great. So for now a DRIVE.D file on the D: drive etc should solve my problem? By the way, I don't think the script checks if an optical drive is a writer or not. I have a script which does that. It's a bit quick and dirty (well more dirty than quick), and quite limited, but it pretty much works. I attached it, feel free adapt it and include in MAPDRIVE, because I've reached the limit of my batcj scripting skills with this. I run it from guirunonce. In an earlier stage I run detectcd (I thin from Icemannd), which writes any CD letters as an environment variable to the registry, then use this to run the script for %%I in (%CDROM1% %CDROM2%) do call %systemdrive%\install\scripts\cd.cmd %%I cd.cmd.txt