on installation, eM Client spent(so far) about 7 hours, flashing back and forth. Won't finish setting up.

on installation, eM Client spent(so far) about 7 hours, flashing back and forth, saying gmail needs a password, but doesn’t present me with a spot where I can type my password. Win10, fully updated.

Go to Windows settings and make sure you have a default web browser selected.

Then restart eM Client. See if there is any difference. If not, remove the account from eM Client in Menu > Tools > Accounts, then add it again.

thanks, but I’ve done that several times. as I stated, I am frustrated.

I am not a GMail user, but I know this has something to do with the 0Auth process. eM Client is waiting for the pop-up window from your browser to complete the process. 

Maybe install another one as a temporary solution. If you are using Chrome, install Firefox and set that as default in Windows settings. Setting the browser as default is very important, otherwise the 0Auth pop-up will not display.