Ever see this statement in the ccmsetup log?  Ever wonder what it means?  When you run CCMSetup again after a failed install there will be a registry entry in place to flag that the previous install was a failure.  It is located at HKLM/Software/Microsoft/ccmsetup.repair.  When this key is present we know the previous install was a failure and restart setup from the beginning, including redownloading all files.  Didn’t see much documentation on this and I found it interesting so thought I’d post it out.