I occasionally see situations where a ERD repair does not seem to work or the results are flaky. It turns out that there is a gotcha ! in the original ERD process. The ERD repair process is driven by the setupdd.sys file. When you choose to replace files during the repair process, this may or may not occur. Setupdd.sys has an override. The emergency repair process searches the Setup.log file for the files to replace. Setupdd.sys compares the files on your HD to the files on the original NT Installation CD. Setupdd.sys compares the Version Resource dates of the HD files to the Version Resource date of the files on the NT Installation CD. If the Version Resource date of a file on the computer is newer, then that file won't be replaced. What's more, the emergency repair process doesn't alert you that the file has not been replaced. A real gotcha!

Microsoft recognized the gotcha! and changed the setupdd.sys file in SP2. The Version Resource date checking feature was disabled. OK. Wonderful! So how does this resolve the issue? It doesn't. To make sure that all files selected during an emergency repair procedure are replaced, you must start the repair process by booting with NT installation diskettes that have an updated setupdd.sys . You replace the setupdd.sys file on disk 2 of the Installation disk set with the Setupdd.sys file from Service Pack 2 or later. If you boot to the NT Installation CD, you will have to create a version with updated setupdd.sys file.