How can I defeat Trustedinstaller so I can run sfc/scannow? I get the "Windows Resource Protection could not start the repair service". I will probably also need it defeated while I replace corrupted/missing system files. I have a crippled Vista machine and a running one with an older Vista installed that I intend to use as a donor for replacement files. When I first started poking around in the crippled one there were two or three restore points saved. I restored the oldest one which was about 7 months old. I was able to run sfc/scannow after that. (I didn't try before that.) After some more poking around I decided to restore to a later restore point, about 3 months old. Now scannow doesn't work. Before the last system restore I saved a system32 directory list (just the root--no subdirectory breakout) to a text file. Comparing it to the directory now, I have exactly the same number of files and subdirectories and the same total size of files, but I now have about 5 Gb less free space on the C:\ drive. I can't account for the extra stuff. I'm not sure exactly how restore works, whether it can restore windows update files contained in the Softwaredistribution\downloads dir. There would be more stuff in there at a later date, but in order for the net change in hard drive space to occur the extra files would have had to have been compressed more than they were when downloaded. Seems far-fetched to me. I did load some files between restore events: a Toshiba value added package that is less than 50 Mb and tsetup.exe that is only 1 Kb. (The Tvap failed to install due to insufficient space on the X:\ drive.) I've done very little registry editing before, but I'm guessing that is the way to do it when I have only the command prompt (Administrator) to work with. Are there arguments that can be put after Trustedinstaller on the command line? When I just type "Trustedinstaller" at the C:\windows\servicing prompt and RETURN, I do not get an error, but I get no indication that anything happened. If I try it from another directory I get the "not recognized" error. I haven't mentioned yet that the restore points are all gone and since I did them from safe mode I can't undo the last one--or so I'm told. Does "can't" mean "impossible" or just "very difficult"?