SCCM 2012 R2 - Install of Management Point Fails - error 1603 - mp.msi could not be installed

Problem:

...having completed the installation of SCCM 2012 R2 you notice that the Management Point has failed to install. You open up the SCCM Console and go to Monitoring > System Status > Site Status you see a red alert symbol next to the Management Point. 

To further confirm the failed install check you open up (%installdirectory%/Microsoft Configuration Manager/Logs/MPSetup.Log) and encounter a number of error messages including, 

"Fatal MSI Error - mp.msi could not be installed"

You may also encounter "mp.msi exited with return code 1603" in the MP.msi.log

You may also open up IIS. You may then notice that it's missing the vast majority of the usual sccm entries under Default Web Site:

Cause:

When the server was built the old SCCM 2007 installed a client onto the server. Even if you already uninstalled the client, there's a good chance that some of the components of the client are still hanging around in the wmi repository. This will interfere with the MP installation to the extent that it will fail.

Solution:

Option A 
Remove the MP from SCCM 2012. Uninstall the 2007 SCCM client by opening an elevated command prompt, navigating to the C:\windows\ccmsetup folder and then entering ccmsetup.exe /uninstall. Reinstall the MP on SCCM 2012.

Option B 
Time to fully clear down the wmi repository of any traces of the old sccm client. Remove the MP from SCCM 2012. Open up Powershell in an elevated command prompt and enter the following command:

Get-WMIObject -namespace "root" -query "SELECT * FROM __Namespace where name = 'ccm'" | remove-wmiobject

Once this has finished running, reinstall the MP on SCCM 2012. Keep an eye on the install process by opening the MPmsi.log and MPsetup.log. It should run with only a few IGNORE errors. When it has finished, open up IIS and confirm that all the rest of the SCCM entries have appeared:

Option C
The nuclear option. Rebuild the sccm server and make damn sure the SCCM client from the old 2007 environement doesn't get installed. This may mean disabling client push in 2007, disabling the install of client install in the build task sequence, building the client in a block GPO OU - whatever you need to do just make sure it never has the 2007 client installed!