Because the information Microsoft gives us is apparently NOT sufficient, I've started to investigate the txtsetup.sif file in detail. And what seems? MassStorage drivers of this kind: cmdide.sys = 1,,,,,,3_,4,1,,,1,4 (note the 3_), are 'BusExtenders' and are therefor listed under [busExtenders] witht their according name. Like this: cmdide = "CMD IDE Bus Driver",files.cmdide,cmdide Yes, that's right it refers to the 'files.cmdide' section, which looks like [files.cmdide] cmdide.sys,4 pciidex.sys,4 AND they're listed here: [BusExtenders.Load] cmdide = cmdide.sys This is why I MUST use 3_ and not 4_ for aliide.sys. EDIT: and maybe for more? But how are these determined? Also, I've noticed some very strange things: ipsraidn, nfrd960, symmpi entries in txtsetup.sif that contain the names only, without any files/driversIf anyone can explain me what I'm doing wrong to get these 'internal data structures corrupted' error, please go ahead!