Like every other day, running Exchange Setups is pretty straight forward, however not so straight forward when the server blue screens on you and you end up with a setup that crashed half way.
In my case I got an error on Step 7 of 9 on the Mailbox role: Client Access service.
As you can see above, not a nice one to have. This means that the PushNotifications virtual directory exists and the setup is trying to create it.
The first place to go to where you can fix this is the following location:
In this folder you have an additional 2x folders and 3 files. The file we will be working with is called ApplicationHost.
I would suggest that you make a backup of this file before modifying it.
You need to look for the location as shown below and you can comment it out and save the file:
I found also deleting the virtual directory from IIS helped.
Once you are done, check that the WMI service is not disabled. Then launch an elevated command prompt and do an IISReset.
Now go back to the setup and launch it and all should succeed.
Hope it helps.