Thanks. I have a seroius problem with HFSLIPFC: IF EXIST SOURCE\WIN51*.* ( SET os=XP ) ELSE IF EXIST SOURCE\cdromsp*.tst ( SET os=2K ) FOR /l %%i in (1,1,5) DO ( IF EXIST SOURCE\cdromsp%%i.tst ( SET sp= ) First code is from HFSLIPFC, second - from my 2K extension. As you can see, both codes are looking for cdromsp*.tst. If that file doesn't exist, it should be only listed as SP0 in my 2K extension, but additionally (due to HFSLIPFC itself) default OS is set to XP!