RESOLVED: A startup screen I've never seen before. Lightening bolt and network icon?

[PinkyMacGodess]

Happened the other day. I ended up holding the button it and it rebooted fine, but this freaked me out a bit. Any idea what would cause this, and is it a symptom of something 'bad' happening? The two icons sort of danced around the screen like a screen saver.

Thanks...

 

[interstella]

That looks like the old target display mode which allowed you to use a Mac as a monitor.

 

[pastoralbasement]

This screen appears to depict "Target Disk Mode", which is activated by holding down the T key during startup. To get out of that mode, hold down the power button until the Mac powers off, perhaps precisely as you have done.

"Target Disk Mode" was a great technology that virtually converted a computer into an external drive. Thus, you could connect the Mac to another 2nd Mac via a FireWire, USB, or Thunderbolt cable. The 2nd Mac would see the 1st Mac as an external drive mounted on the desktop.

Further reading:

1. Apple's current "Target Disk Mode" documentation
2. Article on Wikipedia.

Traditional "target disk mode" was eliminated with the introduction of Apple Silicon.

 

[PinkyMacGodess]

This screen appears to depict "Target Disk Mode", which is activated by holding down the T key during startup. To get out of that mode, hold down the power button until the Mac powers off, perhaps precisely as you have done.

"Target Disk Mode" was a great technology that virtually converted a computer into an external drive. Thus, you could connect the Mac to another 2nd Mac via a FireWire, USB, or Thunderbolt cable. The 2nd Mac would see the 1st Mac as an external drive mounted on the desktop.

Further reading:

1. Apple's current "Target Disk Mode" documentation
2. Article on Wikipedia.

Traditional "target disk mode" was eliminated with the introduction of Apple Silicon.

Best as I can remember, this is what happened. I was plugging in a USB dongle on the end of a USB extension cord, and powered on the Mini. Next I see is that screen. I do have a bobble head Sheldon that was on the keyboard at the time having fallen off the Mini. I doubt that it's likely that light thing pushed on the 't' key hard enough, but I guess possible. Apparently 'target disk mode' isn't dead, or isn't dead on an Intel Mini. So the Mini was a headless file server in essence? Hmm. Interesting niche feature.

Thanks for the info. My history with this Mini did cause a momentary spike on my heart rate.

 

[PinkyMacGodess]

That's actually pretty cool, looking at all the links in Wikipedia for Targeted Disk Mode. From BOOTP, to all of it. Interesting. I did a remote boot PC once. It didn't last long, but as an experiment, it was weird to get it working. That was quite a while before the 'thin client' craze that seems to have largely died. *shrug* Thanks...

 

[joevt]

The Thunderbolt and USB icons on the target Mac's screen means you can connect another Mac to the target Mac using Thunderbolt or USB. Older Macs would show a FireWire icon which means they can connect using FireWire but not USB or Thunderbolt.

 

[PinkyMacGodess]

The Thunderbolt and USB icons on the target Mac's screen means you can connect another Mac to the target Mac using Thunderbolt or USB. Older Macs would show a FireWire icon which means they can connect using FireWire but not USB or Thunderbolt.

I got that, now I'm trying to figure out how it thought I needed that. Strange. Did Sheldon cause it? Hmm...

It seemed, to me, to be connected to me plugging in the dongle/extension cord. My mind was all 'How would that cause it?'. I do have an app that I use with that Mini also freak out. It's an indoor training app (Zwift) and it was having fits of the screen twitching for 6 or 7 seconds, back and forth the same second (like a seizure). Like it was stuck in a time warp. Also trying to do screen caps in the app was freaking it out, and when I went to quit the app, the whole system just went into a quicker twitching fit until I clicked something on the screen to get it out of it. The ride saved, but the experience was intolerable. Wondering if my drama king Mac Mini is having a meltdown, AGAIN.

 

[Amethyst1]

Older Macs would show a FireWire icon which means they can connect using FireWire but not USB or Thunderbolt.

Macs that have both FireWire and Thunderbolt show both logos and support Target Disk Mode using either of them, but not both at the same time.