I have the following message after selecting my Macintosh HD to install the downloaded macOS Sierra. I'm running a 2013 MacBook Air. 
The install seems to be progressing fine, but logging this message in case others have the same problem
	
		
			
		
		
	
				
			The install seems to be progressing fine, but logging this message in case others have the same problem
 
 
		 
 
		