Wrong procedure. DOS 7.1 uses Int13x which supports 48-bit LBA. It has nothing to do with ESDI_506.PDR. ok in extreme detail here is what i did 1. download 4102225F.ZIP and unzip 2. copy esdi_506.pdr to root dir of c: 3. reboot using win98 cd to plain old dos 4. dos commands as follows cd windows cd system cd iosubsys rename esdi_506.pdr esdi_506.bak 5. copy c:\esdi_506.pdr 6. shutdown 7. install 300gb drive as drive d: 8. boot to dos and fdisk drive 9. boot into windows and format drive d: 10 copy lots and lots of files to d: 11 run scandisk and it does not work 12 run defrag and it does not work 13 downloaded this http://rapidshare.de/files/26697545/bhdd20e.zip.html posted by maximus-decim Include: esdi_506.pdr - LLXX version 4.10.2225 (up to version 4.10.2230) defrag.exe - Windows Me dskmaint.dll - Windows Me scandskw.exe - Windows Me format.exe - Free Format 0.91v fdisk.exe - Free Fdisk 1.21 Documentations and Installation 14 installed above per documentation 15 ran scandisk and it worked 16 ran defrag and it works also thats it all done