Seems the permissions have gotten in an odd state so the owner is root but pi can read. if you run something like:
sudo chown -R pi:pi /home/pi
it will set the owner of the pi folder and all subfolder back to pi user. If you are saving to a folder not under /home/pi you’d need to specify that folder.
Sorry, didn’t notice that the roms dir isn’t supposed to be owned by pi so might need to do the following to revert that back
sudo chown root:pi /home/pi/RetroPie/roms
sudo chown root:pi /home/pi/RetroPie/roms/*
sudo chmod g+w /home/pi/RetroPie/roms/*
sudo chown -f -R pi:pi /home/pi/RetroPie/roms/*/*
Tried it, but it still won’t save as pi. My saves are stored at /media/usb/romsaves. I used the command you suggested on both /media/usb and /media/usb/romsaves, but after romsaves it said ‘operation not permitted’ on the three srm files in there. I checked permission using ls -ld and it said pi owned /media/usb, but root owned /media/usb/romsaves.
Ah for usb that is automounting you can modify the /etc/usbmount/usbmount.conf and edit the FS_MOUNTOPTIONS to be something like the following if the drive is vfat FS_MOUNTOPTIONS=”-fstype=vfat,gid=users,uid=nobody,umask=002,sync” which will create the mounts so that all users in the users group can modify them. You can reboot or possibly remove and insert the drive again to have the changes take place.