New Dell XPS-8900 running Win10. I created a Homegroup on the 8900 and joined the Homegroup with my Win8.1 laptop.

When I try to copy a file from the laptop to the 8900 (or from the 8900 to the laptop) I get this error:
..... You need permission to perform this action.
..... You require permission from xxx to make changes to this file. (where xxx is the name of the 8900 or the laptop)

This has to be a Win10 Homegroup problem since that laptop used to work fine on my previous Win7 PC's Homegroup. And the files on my new 8900 PC are on a data hard drive that used to be in my Win7 PC and worked fine with its Homegroup. IOW, all of the data on the laptop and on the new XPS-8900 that used to transfer fine on the Win7 Homegroup, now need permission to transfer on the 8900's Win10 Homegroup.

FWIW, I can assign "Full control" to a file and then it will transfer. But it's too much of a hassle to have to do that for every file I want to transfer.

Any way to fix this globally?