after I switch to Sierra my Mac doesn't recognize my external drive it only recognizes one only I switch cables. used the cables that work but it still doesn't recognize it but my MacBook does, any help please
What model Mac please?
Try another port, assuming your Mac has one.
where do I find the model number. But it does have other ports try all 4 and it still doesn't work
Sometimes, an SMC Reset will fix that problem. Try it: Reset the System Management Controller (SMC) on your Mac - Apple Support.
I did the smc but it still does not recognize it I plug 2 other externals and they work find but just this one is not recognizing but the MacBook still does
Does it appear in Disk Utility? Using Disk Utility to verify or repair disks - Apple Support.
I doubt that it will though.
It is possible for a model-specific bug in Sierra to be responsible, in which case we will just have to wait for Apple to fix it. That possibility is more likely if the drive does not have its own power supply — in other words, if it uses the Mac's USB port for its power.
Sierra doesn't recognize external drive
