Q: rename efi boot windows 10 bootcamp os x imac

you would likely get more success here

Boot Camp

I have renamed BC volumes on W8.1. I do not have a W10 installation handy. Can you run the equivalent process in W10? You will need to use Disk Management.

Can you post the output of diskutil list from the OS X side? Your C: shows BOOTCAMP.

The boot ability is derived from the MSR not the MSD. As a test, please rename disk0s4 to an arbitrary name using diskutil renameVolume.

The syntax is

diskutil renameVolume

Usage:  diskutil rename[Volume] MountPoint|DiskIdentifier|DeviceNode newName

The new name is subject to file system-specific naming restrictions.

Ownership of the specified volume may be required.

diskutil renameVolume disk0s4 <SomeName>

Does the renameVolume generate any errors? What does diskutil list show?

You cannot mount disk0s4 without some additional steps. There is not much which is useful in disk0s4. Can you see Bootcamp volume in OSX Finder?

From Use Windows 10 on your Mac with Boot Camp - Apple Support, your 2011 iMac is not officially supported by Apple for W10 upgrade, even though M$ may say otherwise.

I updated my previous post with supportability of your iMac model. There is a reason to see the EFI Boot. It may be easier to show first rather than to explain.

From OSX Terminal,

sudo mkdir -p /Volumes/EFI

sudo mount -t msdos /dev/disk0s1 /Volumes/EFI

cd /Volumes/EFI

ls -lR

Copy and paste each command in the Terminal. The "sudo" commands will prompt for your password, and it will not be echoed back. You may also see a warning about improper use of "sudo" and potential data loss due to "abuse" of the command.

Hi there, I have tried searching countless of forums but I am still unable to find the solution to this problem. Does anybody know how to resolve this issue?

Thanks.

Have you installed W10 on a 2011 Mac using EFI Boot?