I got the 0x84b30001 error when trying to install the latest Microsoft Assessment and Planning tool (MAP) this evening. Taking a look through the error logs gave me the message “A network error occurred while attempting to read from the file: c:\e….0\x86\setup\x86\sqlncli10.msi”, each time the directory name was different. I tried running the SQL2008 express installation manually and got the same message. However double clicking on the sqlncli10.msi file from the log file would work – or seem to. Trying to do a repair gave me the same message. I then chose to delete the 2008 native client installation (the sqlncli10.msi package) as I knew that a successful installation would result in the client being installed again. The uninstall was successful so I then reran the sql2008 installation with no problems. MAP then installed successfully. I posted a note on the technet forums here in case anyone else has some follow up comments/questions. Now that I’m home I can’t actually run the assessment tool, but I’ll be able to do this tomorrow – hopefully it will give me the results I am after.