Can't hibernate computer MacOS Mojave, no pmset "standby" option
In my case, I had added a SSD to my machine, which I put in the old DVD SATA slot. This is my main system disk, with an HDD in the original hard drive slot for additional storage. It seems that macos can only resume from a harddrive in the original SATA slot. Swapping the two drives fixes the problem for me!