bootable external drive is locked when trying to install any macOS updates
it's a Seagate pocket external and I've tried just about everything.
I'm a long time apple user and getting discouraged with everything coming from cloud or internet downloads
Eggie5776 wrote:
I don't want to update my internal Macintosh HD. I'm running Mojave on it and need to keep it.
Trying to install Monterey on the bootable external to run the newer software
In that case, you need to create a new APFS volume on your external drive.
Follow these steps:
Jack
Eggie5776 wrote:
I don't want to update my internal Macintosh HD. I'm running Mojave on it and need to keep it.
Trying to install Monterey on the bootable external to run the newer software
In that case, you need to create a new APFS volume on your external drive.
Follow these steps:
Jack
What year model is your iMac?
see > Identify your iMac model - Apple Support
Sounds like you need to change the Security settings to allow it to startup from the external disk.
see > About Startup Security Utility on a Mac with the Apple T2 Security Chip - Apple Support
Telling us you have "tried everything" tells us nothing useful, please be detailed about what you have attempted. Also include how the drive is formatted, what you are attempting to do and most importantly the version of Mac OS you are referring to! I think you might also get some useful hints on what we need from you by reading https://discussions.apple.com/docs/DOC-5931ies Question
If you want the external USB hard drive/SSD to contain both the bootable macOS USB installer and the full macOS install for a fully functioning external macOS boot drive, then you need to properly prepare the USB drive to support both. Erase the USB drive as GUID partition and MacOS Extended (Journaled). Then you will need to add a new (second) partition. Make sure the second partition is just large enough to hold the macOS USB installer. Make sure that the first very large partition is erased as APFS (top option) since this will be for the full macOS installation while the second smaller partition is for the USB installer which should be erased as MacOS Extended (Journaled).
Follow Apple's instructions for creating a bootable macOS USB installer making sure to use the volume name for the second partition (the smaller of the two partitions) as the destination when using the Terminal command line for creating the USB installer. When finished, Option Boot the USB drive as before. Now when you click on the "Reinstall macOS" option from the installers menu you should now be able to select the first larger partition as the destination for the full installation of macOS.
FYI, you will now be stuck with an extra smaller partition. It may be possible to delete the smaller partition used for the USB installer and merge it back into the Container for the full macOS boot volume, but macOS can be finicky when modifying partitions. Modifying partitions like this does risk damaging the other partitions on the drive which in this case could possibly damage the new macOS full boot drive if something goes wrong.
Why not just purchase a USB stick to use for the bootable macOS USB installer as that will be so much easier especially if the external drive is a hard drive as opposed to an SSD since you will end up thrashing the heads of the hard drive back and forth during the install process which will make the process take a lot longer than if you had used a USB stick for the macOS installer.
looked at a lot of suggestions on line and so far I've tried using disk utility to format external drive a few different ways, terminal to make drive bootable. Tried Install Disk Creator to format and install Monterey. I'm currently using Mojave and I need to keep it to run my older apps. I seem to be able to make the external seagate drive bootable but I keep getting the message that the drive is locked when I go to install the OS Monterey
I've tried formatting drive APFS, GUID Partion Map, also tried OS Extended Journaled. After using terminal to make drive bootable I get the same result when trhing to install Monterey. as per the photo, it says the drive is locked.
Welcome to the Apple Support Communities.
You are trying to install on your bootable media. Select “Macintosh HD” as the target for installation.
Jack
I don't want to update my internal Macintosh HD. I'm running Mojave on it and need to keep it.
Trying to install Monterey on the bootable external to run the newer software
Oh My God, Thank you, I've been working on this for four days now and this is working.
Thank you, thank you, thank you.
bootable external drive is locked when trying to install macOS
