The bless tool was unable to set the current boot disk?

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Level 1

125 points

The bless tool was unable to set the current boot disk?

(Repost from MACOS forum, probably more appropriate here than there)

Hi all,

I recently bought a MacBook Pro and decided to keep windows on an external ssd. I was able to install it fine and it all works with one exception - I can not switch disks via Startup Disk as I get this error:

I can book into Boot Camp fine by holding the Option key but would like to get this working as well. Google said that it maybe EFI related but I confirmed the SSD has EFI using Winclone so not sure where too now?

Thanks in advance.

MacBook Pro with Touch Bar

Posted on Sep 22, 2019 11:54 PM

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Answer 1

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Loner T

Level 9

59,471 points

Sep 24, 2019 4:01 AM in response to solomani

solomani wrote:

Yeah, I am not calling Bless its Startup Disk/OS that is :)

Bless is not called when you boot and hold Alt/Option. 😉

Yes it is EFI boot.

I suggest using Alt/Option.

Why is bless complaining if anyone knows?

See the previous post.

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Answer 2

Loner T

Level 9

59,471 points

Sep 23, 2019 2:54 AM in response to solomani

Bless is a legacy tool and should not be used. You will run into challenges with external disks. This is not officially supported by Apple or Microsoft, unless you have a Windows2Go license.

Is Windows installed using EFI Boot?

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Answer 3

Loner T

Level 9

59,471 points

Sep 24, 2019 3:59 AM in response to TonOT1

TonOT1 wrote:

Uhhhh, Bless is called implicitly by the standard OS-function "System preferences".....

Bless is used for Legacy BIOS installations of Windows. The Windows on external disk is assumed to be BIOS by System Preferences.

Look at the first picture.... Perhaps Apple should read you remark;-)

See the man page of the systemsetup command. Specifically the following options

[-getstartupdisk] [-liststartupdisks] [-setstartupdisk path]

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Answer 4

Sep 23, 2019 12:05 AM in response to solomani

Have you tried everything on this page? How to select a different startup disk - Apple Support

If this doesn’t work you should probably contact official Apple support

Official Apple Support

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Answer 5

solomani Author

Level 1

125 points

Sep 23, 2019 12:07 AM in response to Person_2099

Yep, startup manager works fine - so I can actually switch OS - I just can't do it directly from MacOS. I only get the error from the Startup Disk menu.

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