Can't boot external

[DanL]

Sheesh. All kinds of problems today.

I can't get my Mac to boot from an external drive. These drives are routinely updated with bootable backups, and finder shows that they are all mounted. But I restart holding down the OPTION key, and it goes straight to the login panel. Huh? I last did an external boot a year ago, so I know it should work. I have three drives attached with bootable backups. Tried resetting PRAM and SNC. No joy. BTW, my OPTION key *does* work.

 

[Cory Cooper]

Hello,

Can you see and choose them in  > System Preferences... > Startup Disk?

C

 

[DanL]

Yes, they are all there. But interestingly they are all greyed out unless I unlock as Administrator.

 

[Cory Cooper]

Yes, that is correct. They will be listed but not accessible until you authenticate - even when logged in as an admin.

C

 

[DanL]

I've heard something about having to "bless" a disk before you boot from it. Never had to do that. Do I suddenly have to do it, I wonder?

 

[Spawn_Dooley]

I've read about the bless command before but for any of the bootable backups I've created using SuperDuper I've never ever had to do any blessing myself. I wouldn't even know how to either.

 

[DanL]

Yep. Just to review, my SuperDuper scheduled backups go off without a hitch. I can successfully boot to any of these backup volumes by selecting them in System Preferences->Startup Disk. So to the extent they need to be blessed to be a bootable backup, they work fine. They are mounted! Icon on the desktop. What I cannot do is select to do an external boot to one of them by holding the OPTION key down when I restart. This used to work! When I do that -- restart while holding down the OPTION key, it goes straight to the login pane of my internal disk. My OPTION key works fine, BTW. For example, I hold it down and pull down the speaker icon in the menubar, and I am able to change speakers. Weird. Also, BTW, my disks are not connected through a USB hub. Straight into the Mac. Also, I am not using a Bluetooth keyboard. I understand that with a Bluetooth keyboard, the OPTION key may not be recognized at startup time.

This is a situation where the Startup Manager is not invoked by pressing the OPTION key at startup.

 

[honestone]

I also use SuperDuper!, along with OS 10.13.3, and the Option key method works for me. However, my internal drive (for each of my Macs) and my external ones are all SSDs. The internal ones are formatted as APFS, and for two of the three partitions on each external SSD (dedicated for SuperDuper! backups), they are formatted as APFS. (The third partition, used for storing various "stuff", is formatted as Mac OS Extended (Journaled)) They can be formatted as Mac OS Extended (Journaled), and in fact, when I initially upgraded to High Sierra, they were formatted that way, but I do remember one instance where I had a similar issue with the Option key method.

High Sierra, on a fresh, clean installation, does first format an internal SSD as APFS, but for external devices/partitions, one must do it via the version of Disk Utility contained within High Sierra. Not sure about the Option key method when one has an HDD as an external drive. SuperDuper! still works fine in that case.

 

[DanL]

OK, I have the answer. My keyboard was connected to my iMac through a powered USB hub. Now, I've heard that those hubs can mess with things on power-up, and it sure does here. I plugged the keyboard directly into the Mac, and bingo! it works. The OPTION key now starts up the Startup Manager on restart just like it should. When the keyboard goes through the hub, the OPTION key isn't read at startup. Not quite sure why, but it isn't. I can imagine that other keys aren't read at startup either. So the lesson is ALWAYS PLUG YOUR KEYBOARD DIRECTLY INTO YOUR MAC IF YOU WANT THINGS TO WORK RIGHT AT STARTUP!!! That ought to be engraved on Mac keyboards.

This always used to work and, just a month ago, I got a powered USB hub. That's what changed. That hub is wonderful when you've got a lot of things connected, but it does have this one major fault.

 

[honestone]

Doesn't your iMac have USB 3.0 ports? My late 2012 Mac Mini does. I've been using a separate Apple keyboard for as long as I can remember, and I've always had it plugged in directly to the Mac.

I also have a USB 3.0 hub, but it is not a "powered" one, that is, it does not draw its power from my Mac Mini. It is plugged in. Not sure what would happen if I plugged my Apple keyboard into it, but I am good the way things are.

 

[DanL]

Well, sure, I have a few USB ports, but I have half a dozen USB peripherals, and I need a hub. An unpowered hub caused me a lot of grief, in that at least the mouse and keyboard operated sketchily with it with all the other stuff plugged in. Moving to a powered hub made all the difference in the world. Not at all clear that a powered hub was the problem here, as opposed to an unpowered hub, but I suspect the hub-ness in general was at fault.

In principle, one can plug *everything* into the hub. There is loads of power for everyone. That's why I plugged my keyboard into it. In practice, evidently not.

 

[honestone]

As I mentioned, I have a "non-powered" USB hub. That is, the hub does not draw its power from my Mac (Mac Mini in my case), as it is plugged into an outlet (actually one of the outlets on my Kensington "Master Piece" HomeOffice device (kind of a decent picture: https://www.cnet.com/products/masterpiece-home-office-6rcptl-surge-420j-25k/specs/)). I have had it for almost forever, and it still works flawlessly!

 

[DanL]

What you have is called a "powered hub", because it attaches to an external power source. An "unpowered hub" gets its power from the Mac USB port itself. You don't plug it in to an outlet.

 

[honestone]

Too bad the terminology is not more straight forward. I've actually heard that a "powered" hub is one that draws its power from the Mac. I guess folks don't believe in the KISS philosophy: Keep It Simple, Stupid.