No problem. I found another problem with an update, not hotfix: KB906569 (updates msconfig and xpsp3res.dll). Could you please take a look? I played a bit with hfslip and could get no solution for this. It is an SP2QFE update, and hfslip deletes SP2QFE folders and infs, to get it working I had to create an switchless installer. I didn´t want to change the type 1 slipstreaming code. Maybe you can find something. Edit: A suggestion: Playing around with this issue, I got an idea for hfslip: While slipstreaming KBxxxxxx.exe and there is no filecopy to WORK\I386X could you may include a kind of "debug.log" for this? So it will be easier to find those kind of errors. The "normal" updates are not scanned by hfnetchk or mbsa and there is no guarentee that they are really integrated. And there are many of them, as you can see here: http://www.pc-experience.de/wbb2/thread.php?threadid=12223 Edit2: Um , this is even more worse then I thought. The following os updates, non sec, don´t get integrated when using hfslip (placed in HF folder): 885626 885884 886677 890831 884883 886716 885222 889016 893357 896626 903224 889527 907865 All these are SP2QFE type ONLY updates. There are probably more. Some of them are not needed (if you don´t use OfficeXP, Adobe Premiere etc.), but some of them are.