I run a MacMini with Mac Sierra and 16GB memory. I have split this down to 8GB for Mac OS and 8Gb for Windows running on Parallels. Everything ran smoothly. Since the last update of Parallels, I now get a message everytime I launch Windows 10 that my allocated memory is outside the recommended memory allocation range (which is a maximum of 4GB) - this never used to happen. I use Windows 10 pretty exclusively on PCs and know from experience that it runs a lot better on 8GB than 4GB. In fact, if you wish to run a few programs in parallel (no pun intended), 4GB struggles. I just delete the message and carry on, but it is a bit annoying. Is there a technical reason why I should restrict the memory allocation to 4GB? If not, how can I get rid of the nagging message at launch of Windows?
Please, send us problem report and post its id here. For this open Parallels Destkop, in its Mac app menu go to Help -> Send Technical Data.