Page 1 of 1

My iMac can default boot to external usb drive?

Posted: Sat Jul 18, 2020 6:23 am
by DaleRaynor
Hi. I've been booting an iMac to an external usb drive w/Linux for a while now. Just recently I've noticed that the iMac can get in a mode where it will boot directly to the ext. usb drive without having to press the "Option" key at start up! Just leaving the usb cable attached at start up causes the iMac to bypass the macos and boot directly to the external drive! I don't recall it doing this before. Also, Strartup Disk utility never shows the external drive as an option.

Is this normal or am I looking at a potential problem ? Thanks.

Re: My iMac can default boot to external usb drive?

Posted: Sat Jul 18, 2020 6:28 am
by Pierre
it's probably not normal, and you could risk the Integrity of the drive, as well.

like the Windows System, it's wise to have any external HDDs off-line, when Booting the machine,
and only power them up, after the machine has an working desktop.

Re: My iMac can default boot to external usb drive?

Posted: Sun Jul 19, 2020 8:45 pm
by jamiemint
This is not likely to be a problem. The mac stores its preference for startup disk in parameter RAM or NVRAM. You can reset these by restarting and pressing command-option-P-R as described here. I've seen the startup disk preference get messed up during a crash.

Jamie

Re: My iMac can default boot to external usb drive?

Posted: Mon Jul 20, 2020 7:22 am
by 1NEWLINUXUSER
Hey DaleR! Couldn't you have at least changed a word or two from my post 7/13: viewtopic.php?f=90&t=324858 ?
Well, I guess no real harm done, at least your post got a response! Thank for that! :P

My iMac can default boot to external usb drive?

Post by 1NEWLINUXUSER » Mon Jul 13, 2020 5:42 pm
Hi. I've been booting an iMac to an external usb drive w/Linux for a while now. Just recently I've noticed that the iMac can get in a mode where it will boot directly to the ext. usb drive without having to press the "Option" key at start up! Just leaving the usb cable attached at start up causes the iMac to bypass the macos and boot directly to the external drive! I don't recall it doing this before. Also, Strartup Disk utility never shows the external drive as an option.

Is this normal or am I looking at a potential problem ? Thanks.

Re: My iMac can default boot to external usb drive?

Posted: Mon Jul 20, 2020 5:33 pm
by 1NEWLINUXUSER
jamiemint wrote:
Sun Jul 19, 2020 8:45 pm
This is not likely to be a problem. The mac stores its preference for startup disk in parameter RAM or NVRAM. You can reset these by restarting and pressing command-option-P-R as described here. I've seen the startup disk preference get messed up during a crash.

Jamie
On behalf of DaleRaynor and myself I'd like to thank you both for responding to our post! :lol: Actually I did try the nvram reset once and it didn't work but I think I may not have waited for the second start up sound as suggested in the link, so will have to try again. Thanks again!