Flash os fail when tried to flash follow instruction

Just got a meadow F7 yesterday and followed instructions to flash the os,
but always get the message:
Unable to flash Meadow OS

Tried the same thing on both Windows 10 and MAC … both fail

.Net wont let me deploy because the firmware OS is old … version 5 or something

Please Help

What Mac HW and OS version are you using?
When you type meadow --version on the command line what does it say?