Unable to create system image windows 10

I have dell precision tower 5810.
Recent crash. installed new 2 tb drive and clean install windows 10
Updated all drivers from dell. I was able to create system image to a 10 gb flash drive. However when trying to create same image file and save to EITHER external 5tb seagate drive or blank additional 2 tb internal drive (e), i get message there is not enough room on drive. System image drive is only 300gb, so there is plenty of room. Any help greatly appreciated