Rename external volumes shown in Startup Manager

The following guide describes the process I went through to change the name shown in Startup Manager for the Boot Camp and macOS installations that I have on my external drive. The steps below might not work for your setup (for example, if you have Boot Camp installed on your internal drive). Proceed with caution, as you might not be able to reverse the changes (at least not easily).

Rename Boot Camp (Windows) volume

1. Open Terminal. Run the following command to list all external disks. Enter an administrator password if/when prompted.

sudo diskutil list external

2. Find the EFI volume and note its identifier (usually it's diskXs1, where X is an integer). For me, having only one external drive connected, the identifier was disk2s1.

3. Run the following command to mount the EFI volume.

   • Replace disk2s1 with the volume identifer noted from the previous step if they're different.

sudo diskutil mount disk2s1

4. Open the EFI directory inside the EFI volume.

open /Volumes/EFI/EFI/

5. Find and note the directory containing the bootx64.efi file. Usually, it's Boot/ (/Volumes/EFI/EFI/Boot/), but I'm not certain this is always the case.

6. Back in the terminal, run the following command to bless and set a label for the Boot/ directory. This will change the name of the Boot Camp volume shown in the Startup Manager.

   • Replace /Volumes/EFI/EFI/Boot/ with the path to the directory found in the previous step if they're different.
   • Replace Windows with any name of your choice.

sudo bless --folder /Volumes/EFI/EFI/Boot/ --label "Windows"

To undo this modification, remove the .disk_label and .disk_label_2x files from Boot/. Replace /Volumes/EFI/EFI/Boot/ with the path to the directory containing the bootx64.efi file if they're different. This worked for me but I don't guarantee it will for you.

cd /Volumes/EFI/EFI/Boot/
rm -f .disk_label .disk_label_2x

Rename macOS volume

Note: The steps below have only been tested with a macOS Catalina (10.15.7) installation.

1. Open Terminal. Run the following command to list all external disks. Enter an administrator password if/when prompted.

sudo diskutil list external

2. Find the Preboot volume and note its identifier. For me, having only one external drive connected, the identifier was disk3s2.

3. Run the following command to mount the Preboot volume.

   • Replace disk3s2 with the volume identifer noted from the previous step if they're different.

sudo diskutil mount disk3s2

4. Open the Preboot/ volume.

open /Volumes/Preboot/

5. Copy the name of the UUID-named directory (e.g. B3C4A1DC-6BA4-11ED-A1EB-0242AC120002).

6. Back in the terminal, run the following command to bless and set a label for the CoreServices/ directory. This will change the name shown for volume containing the macOS installation in the Startup Manager.

   • Replace B3C4A1DC-6BA4-11ED-A1EB-0242AC120002 with the UUID found in the previous step.
   • Replace Macintosh eHD with any name of your choice.

sudo bless --folder /Volumes/Preboot/B3C4A1DC-6BA4-11ED-A1EB-0242AC120002/System/Library/CoreServices/ --label "Macintosh eHD"

To undo this modification, remove the .disk_label and .disk_label_2x files from CoreServices/. Replace B3C4A1DC-6BA4-11ED-A1EB-0242AC120002 with the UUID found earlier. This worked for me but again, I don't guarantee it will for you.

cd /Volumes/Preboot/B3C4A1DC-6BA4-11ED-A1EB-0242AC120002/System/Library/CoreServices/
rm -f .disk_label .disk_label_2x