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sandssmith Author

Level 1

4 points

I keep getting this error when trying to make a USB thumb into a Big Sur bootable installer

I'm looking for help. I have tried two different USB thumb drives, but I continue to get an error at the end of the process in Terminal.

Here is the Terminal info:

Last login: Mon Feb 22 00:17:15 on console

Steves-MacBook-Pro:~ admin$ sudo /Applications/Install\ macOS\ Big\ Sur.app/Contents/Resources/createinstallmedia --volume /Volumes/BigSur

Password:

Ready to start.

To continue we need to erase the volume at /Volumes/BigSur.

If you wish to continue type (Y) then press return: y

Erasing disk: 0%... 10%... 20%... 30%... 100%

Copying to disk: 0%... 10%... 20%... 30%... 40%... 50%... 60%... 70%... 80%... 90%... 100%

Making disk bootable...

Couldn't mount dmg /Volumes/Install macOS Big Sur/Install macOS Big Sur.app/Contents/SharedSupport/SharedSupport.dmg (error code 110)Couldn't find InstallInfo.plist

The bless of the installer disk failed.

More info: 2 TB USB Thumb drive

Reformatted to MacOS Extended (Journaled)

The 'parent' drive is GUID partition format.

Performing all of this on a MacBook Pro (Retina, 13-inch, Early 2015)

What am I doing wrong?

MacBook Pro 13″, macOS 10.14

Posted on Feb 22, 2021 9:19 AM

Top-ranking reply

VikingOSX

Community+ 2024

Level 10

116,759 points

Posted on Feb 22, 2021 9:36 AM

If you are using any anti-virus software on this Mac, either disable or better, remove it before running the following.

Try with an unformatted, unused 16 - 32 GB USB thumb drive. Does not need to be pre-formatted as the createinstallmedia will do all that for you. Just use the default name of the mounted thumb drive.

If the second paragraph fails again, then there is either something going on with your Mojave installation, or the Big Sur installer was damaged in the download process. You might consider removing it and redownloading it from the Mac App Store before attempting to create the bootable thumb drive.

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I keep getting this error when trying to make a USB thumb into a Big Sur bootable installer

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