Can I delete an unused (Windows) EFI entry?

[joneall]

I had a trial version of Windows 11 on a computer I just acquired. Here's my efi partition.

sudo ls -l /boot/efi/EFI
total 12
drwx------ 2 root root 2048 Jul 10 14:51 Boot
drwx------ 4 root root 2048 Jul 10 15:43 Microsoft
drwx------ 2 root root 2048 Jul 11 16:40 neon
drwx------ 6 root root 2048 Jul 21 07:50 refind
drwx------ 2 root root 2048 Jul 10 17:41 tools
drwx------ 2 root root 2048 Jul 10 14:51 ubuntu

Can I delete the Microsoft entry without breaking anything?

[barfly]

I can't see why that would affect any other entries, but as usual, make a backup first - just in case.

[kc1di]

If you are talking about the efi boot then you can delete them with this command
first list the active ones.

efibootmgr list

Then delete unwanted ones with the command

sudo efibootmgr -B -b <boot code>

Replace the boot code with the actual number of the item you want to delete.
Example: sudo efibootmgr -B -b 0001 (would usually be the second item in the list.)
Good luck.

[Qqmike]

I assume you are successfully booting the computer using rEFInd, Neon, or ubuntu (your Kubuntu).
If so, you could actually go into /EFI and delete the folder for Windows, for this: drwx------ 4 root root 2048 Jul 10 15:43 Microsoft.
This folder: /boot/efi/EFI/Microsoft, it looks like.
I think that BOOT is a standard backup, but not sure, hopefully Windoiws is not tied to it--You can make anything tied to it, even grubx64.efi.
To get into the ESP, as root, you can use Krusader.
Or, maybe the command line, using sudo -i.
Be careful! But ... you got rEFInd, which should rescue you from (almost) anything.