Thanks Arno1. You are correct we are on the same page, the issue is the difference in IO performance for a file residing on a virtual HDD of a VM and one residing in the MacOS - accessed by Parallels. Thank you for clarifying that well. If I understand correctly, this is standard operating behavior. As for the 'lag' time, I have yet to quantify the delay (I have not had the time pun maybe/not intended). The two most noticeable lag times are perceived when installing an application on Windows 10 from a shared MacOS "Downloads" folder. The second one is when running a Windows 10 disk cleanup - when compared to other VM platforms (w/ cloned HDD for VM instances).
It seems that for a Windows application that calls a json config file often from a shared MacOS directory, the delay can be long enough to crash the windows application. The app checks the config file every 10sec.
Last edited: Feb 14, 2018