I was using a scanning tool to scan some servers and workstations. I could pull some information from the scan, but it would fail when attempting to collect information via Remote Registry. After checking that the Remote Registry service was started and the firewall was not enabled, I attempted to connect to one of the systems remotely using regedit instead of the scanning tool. The connection would appear to succeed, but as soon as I attempted to click on an entry, I would get an error message “Cannot open HKEY_LOCAL_MACHINE: Error while opening key.” [more]After doing some research, I found this TechNet article (http://support.microsoft.com/kb/892192). It explains that systems that were upgraded from Windows 2000 may experience this issue because Windows 2000 ran Remote Registry under the “Local System” account, while XP/Server 2003 runs it under the “Local Service” account. Once you give “Local Service” read access to a specific registry subkey on the target system, Remote Registry works.