Hi all! 1) If Windows Media Format v9.5 (wmfdist95.exe) is being installed, HFSLIP doesn't update the file mp4sdmod.dll from KB975558 hotfix (at least on my XP). This causes Windows Update to suggest this package even if it was already included in compilation. As far as I can tell, that's because if wmfdist95.exe is found in HF\ directory, the script sets its MPLEVEL variable to "42" (line 1482), but for value "42" only WMP10, WMP10L, and WM10L subdirectories in hotfixes are defined (line 476). In KB975558 package there are two mp4sdmod.dll files, located in WM9 and WM10 subdirectories. The script doesn't know about WM10 nor look in WM9 and therefore doesn't update the DLL. It can be fixed, for example, by adding WM10 in line 476: IF "%MPLEVEL%"=="42" SET MPFLDRA=WMP10&SET MPFLDRB=WMP10L&SET MPFLDRC=WM10L&SET MPFLDRD=WM10 Then script will use WM10\mp4sdmod.dll file. Note that this will update the codec to version 10.0.0.xxxx. The hotfix itself takes version 9.0.0.xxxx even if WMF9.5 was installed, but most of WMF9.5 files are v10, so this probably shouldn't cause any troubles. The hotfix updates it to v10 as well. Also, one more thing about WM8 decoder handling from this hotfix. Maybe the line 1624 IF EXIST TEMP\WM8\mpg4ds32.ax MOVE/Y TEMP\WM8\mpg4ds32.ax TEMP >NUL could be replaced with IF EXIST TEMP\WM8 MOVE/Y TEMP\WM8\* TEMP >NUL and moved to "%VERSION%"=="XP" branch of the above IF operator (line 1575), like in its "%VERSION%"=="2000" branch. This could be useful for possible future WM8 hotfixes on XP. 2) A little note about registry file for KB2264107 hotfix (WindowsXP-KB2264107-x86.reg) given on Mim0's site. It sets the value "HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\CWDIllegalInDllSearch" to 0xFFFFFFFF, which means "exclude current working directory from DLL search paths" (support.microsoft.com/kb/2264107). Looks like this also prevents applications from searching their files in paths relative to current. In particular, HFSLIP itself can not unpack some hotfixes on system with this parameter set to 0xFFFFFFFF (because it runs them with relative paths - like "HF\HotFix.exe /X:TEMP"). If turn silent mode off, they gives "file is corrupt" errors (but runs OK if CWDIllegalInDllSearch is not FFFFFFFF). Therefore, maybe it's better to set this value to "1" (always exclude only network current working directory) or to "2" (exclude network CWD for applications started locally, but allow it if program was started from network). IMHO, 2 is more universal and preferable. I have attached both examples. Thanks for developing this project! P. S. By the way, the version of HFSLIP I'm referencing to is hfslip-1.7.10_beta_J_v10 edition by Mim0. hfslip-1.7.10_beta_J_v10_test.zip WindowsXP-KB2264107-x86_value_2.zip