The Microsoft error code lookup tool (which no Windows admin should be without) got updated today: http://www.microsoft.com/downloads/details.aspx?familyid=be596899-7bb8-4208-b7fc-09e02a13696c&displaylang=en&tm.
While it says it’s for Exchange, it really covers Exchange, Windows and a number of other Microsoft products. You can plug an error code in and this tool will give you whatever definitions it finds in the headers compiled into it. If you’ve ever seen an event that says “the error code is in the data”, or you get a message that “unknown error 0x80045500” has occurred and you have no idea what to do, this is where to start. I keep the binary in the path on my workstations. Here’s a sample for one of the most common codes you’ll see:C:\Documents and Settings\Administrator>err c0000005
# for hex 0xc0000005 / decimal -1073741819 :
# The instruction at “0x%08lx” referenced memory at
# “0x%08lx”. The memory could not be “%s”.
# 2 matches found for “c0000005”
Generally speaking the correct result is the first one for this example. When you get more than one result though you’ll have to look at the names of the header files (e.g. usb.h) and see which one makes sense.