I have several boot drives in my Mac Pro, each with different operating systems. Right now, I have Sierra, Yosemite, and Windows 10. I use
vifs to edit the fstab file, to prevent other volumes from mounting automatically at boot. But under Sierra, this is sometimes ignored, and the other two volumes are mounted automatically at boot. I never have this problem under Yosemite. The strange thing is, it doesn't happen every time. Sometimes when I boot Sierra, the other two volumes are mounted, and sometimes they are not. Below is the contents of my fstab from Sierra.
# # Warning - this file should only be modified with vifs(8) # # Failure to do so is unsupported and may be destructive. # #Windows UUID=0EC23A58-2503-48E4-88FB-3F13F1F80F6A none ntfs ro,noauto # #yosemite UUID=66A393D3-C723-42D6-89A3-EA68B961FFF3 none hfs rw,noauto