Renames MIDI ports as displayed by the Windows 10 / WinRT MIDI API. Requires your customization to work correctly. Only impacts apps using the WinRT MIDI API, not the Win32 MIDI API.

RenameMidi.ps1

# This will rename ports for use with the Windows 10 MIDI API (does not impact the Win32 port names)
#
# Created by Pete Brown : Twitter @pete_brown
#
# Unofficial and not supported by Microsoft. This is a workaround, not a proper solution.
#
# This must be run from administrator PowerShell on the target PC
#
# You must re-run this any time devices or drivers change, or they are re-enumerated. At a minimum, this
# tends to be on each reboot or system update. This is basically updating a name cache, not making changes
# to the source of the names. 
#
# Note that the IDs can change if you add/remove devices, rebuild your PC, etc.
#
# Before running, change the actual paths in the Set-ItemProperty statements to match the MIDI devices you want to rename
# You can find the appropriate paths by going into the input and output hives in the registry and looking at the current
# FriendlyName property values.
#
# ============================================================================================================
# Back up your registry values before running this. No warranty, and you are 100% at your own risk 
# by running this script or any variation or derivation of it.
# ============================================================================================================

# Hives for input and output information

$midiInHive = "HKLM:\SYSTEM\ControlSet001\Control\DeviceClasses\{504be32c-ccf6-4d2c-b73f-6f8b3747e22b}\"
$midiOutHive = "HKLM:\SYSTEM\ControlSet001\Control\DeviceClasses\{6dc23320-ab33-4ce4-80d4-bbb3ebbf2814}\"

# Change Outputs

# I have two MOTU 8 port MIDI Express 128 on my PC, and I prefer they have a nicer name than just "MIDI" for each port.

Set-ItemProperty -path "$midiOutHive##?#SWD#MMDEVAPI#MIDII_A5532C41.P_0000#{6dc23320-ab33-4ce4-80d4-bbb3ebbf2814}\#\Device Parameters" -name "FriendlyName" -value "MOTU MIDI 1 Port 1 - EX-8000"
Set-ItemProperty -path "$midiOutHive##?#SWD#MMDEVAPI#MIDII_A5532C42.P_0000#{6dc23320-ab33-4ce4-80d4-bbb3ebbf2814}\#\Device Parameters" -name "FriendlyName" -value "MOTU MIDI 1 Port 2"
Set-ItemProperty -path "$midiOutHive##?#SWD#MMDEVAPI#MIDII_A5532C43.P_0000#{6dc23320-ab33-4ce4-80d4-bbb3ebbf2814}\#\Device Parameters" -name "FriendlyName" -value "MOTU MIDI 1 Port 3 - D-550"
Set-ItemProperty -path "$midiOutHive##?#SWD#MMDEVAPI#MIDII_A5532C44.P_0000#{6dc23320-ab33-4ce4-80d4-bbb3ebbf2814}\#\Device Parameters" -name "FriendlyName" -value "MOTU MIDI 1 Port 4 - MKS-50"
Set-ItemProperty -path "$midiOutHive##?#SWD#MMDEVAPI#MIDII_A5532C45.P_0000#{6dc23320-ab33-4ce4-80d4-bbb3ebbf2814}\#\Device Parameters" -name "FriendlyName" -value "MOTU MIDI 1 Port 5"
Set-ItemProperty -path "$midiOutHive##?#SWD#MMDEVAPI#MIDII_A5532C46.P_0000#{6dc23320-ab33-4ce4-80d4-bbb3ebbf2814}\#\Device Parameters" -name "FriendlyName" -value "MOTU MIDI 1 Port 6"
Set-ItemProperty -path "$midiOutHive##?#SWD#MMDEVAPI#MIDII_A5532C47.P_0000#{6dc23320-ab33-4ce4-80d4-bbb3ebbf2814}\#\Device Parameters" -name "FriendlyName" -value "MOTU MIDI 1 Port 7 - DW-8P"
Set-ItemProperty -path "$midiOutHive##?#SWD#MMDEVAPI#MIDII_A5532C48.P_0000#{6dc23320-ab33-4ce4-80d4-bbb3ebbf2814}\#\Device Parameters" -name "FriendlyName" -value "MOTU MIDI 1 Port 8"

Set-ItemProperty -path "$midiOutHive##?#SWD#MMDEVAPI#MIDII_AD021E81.P_0000#{6dc23320-ab33-4ce4-80d4-bbb3ebbf2814}\#\Device Parameters" -name "FriendlyName" -value "MOTU MIDI 2 Port 1 - Mono Lancet"
Set-ItemProperty -path "$midiOutHive##?#SWD#MMDEVAPI#MIDII_AD021E82.P_0000#{6dc23320-ab33-4ce4-80d4-bbb3ebbf2814}\#\Device Parameters" -name "FriendlyName" -value "MOTU MIDI 2 Port 2"
Set-ItemProperty -path "$midiOutHive##?#SWD#MMDEVAPI#MIDII_AD021E83.P_0000#{6dc23320-ab33-4ce4-80d4-bbb3ebbf2814}\#\Device Parameters" -name "FriendlyName" -value "MOTU MIDI 2 Port 3"
Set-ItemProperty -path "$midiOutHive##?#SWD#MMDEVAPI#MIDII_AD021E84.P_0000#{6dc23320-ab33-4ce4-80d4-bbb3ebbf2814}\#\Device Parameters" -name "FriendlyName" -value "MOTU MIDI 2 Port 4"
Set-ItemProperty -path "$midiOutHive##?#SWD#MMDEVAPI#MIDII_AD021E85.P_0000#{6dc23320-ab33-4ce4-80d4-bbb3ebbf2814}\#\Device Parameters" -name "FriendlyName" -value "MOTU MIDI 2 Port 5"
Set-ItemProperty -path "$midiOutHive##?#SWD#MMDEVAPI#MIDII_AD021E86.P_0000#{6dc23320-ab33-4ce4-80d4-bbb3ebbf2814}\#\Device Parameters" -name "FriendlyName" -value "MOTU MIDI 2 Port 6"
Set-ItemProperty -path "$midiOutHive##?#SWD#MMDEVAPI#MIDII_AD021E87.P_0000#{6dc23320-ab33-4ce4-80d4-bbb3ebbf2814}\#\Device Parameters" -name "FriendlyName" -value "MOTU MIDI 2 Port 7"
Set-ItemProperty -path "$midiOutHive##?#SWD#MMDEVAPI#MIDII_AD021E88.P_0000#{6dc23320-ab33-4ce4-80d4-bbb3ebbf2814}\#\Device Parameters" -name "FriendlyName" -value "MOTU MIDI 2 Port 8"


# Change Inputs

Set-ItemProperty -path "$midiInHive##?#SWD#MMDEVAPI#MIDII_A5532C41.P_0003#{504be32c-ccf6-4d2c-b73f-6f8b3747e22b}\#\Device Parameters" -name "FriendlyName" -value "MOTU MIDI 1 Port 1"
Set-ItemProperty -path "$midiInHive##?#SWD#MMDEVAPI#MIDII_A5532C42.P_0003#{504be32c-ccf6-4d2c-b73f-6f8b3747e22b}\#\Device Parameters" -name "FriendlyName" -value "MOTU MIDI 1 Port 2"
Set-ItemProperty -path "$midiInHive##?#SWD#MMDEVAPI#MIDII_A5532C43.P_0003#{504be32c-ccf6-4d2c-b73f-6f8b3747e22b}\#\Device Parameters" -name "FriendlyName" -value "MOTU MIDI 1 Port 3"
Set-ItemProperty -path "$midiInHive##?#SWD#MMDEVAPI#MIDII_A5532C44.P_0003#{504be32c-ccf6-4d2c-b73f-6f8b3747e22b}\#\Device Parameters" -name "FriendlyName" -value "MOTU MIDI 1 Port 4"
Set-ItemProperty -path "$midiInHive##?#SWD#MMDEVAPI#MIDII_A5532C45.P_0003#{504be32c-ccf6-4d2c-b73f-6f8b3747e22b}\#\Device Parameters" -name "FriendlyName" -value "MOTU MIDI 1 Port 5"
Set-ItemProperty -path "$midiInHive##?#SWD#MMDEVAPI#MIDII_A5532C46.P_0003#{504be32c-ccf6-4d2c-b73f-6f8b3747e22b}\#\Device Parameters" -name "FriendlyName" -value "MOTU MIDI 1 Port 6"
Set-ItemProperty -path "$midiInHive##?#SWD#MMDEVAPI#MIDII_A5532C47.P_0003#{504be32c-ccf6-4d2c-b73f-6f8b3747e22b}\#\Device Parameters" -name "FriendlyName" -value "MOTU MIDI 1 Port 7 - DW-8P"
Set-ItemProperty -path "$midiInHive##?#SWD#MMDEVAPI#MIDII_A5532C48.P_0003#{504be32c-ccf6-4d2c-b73f-6f8b3747e22b}\#\Device Parameters" -name "FriendlyName" -value "MOTU MIDI 1 Port 8"

Set-ItemProperty -path "$midiInHive##?#SWD#MMDEVAPI#MIDII_AD021E81.P_0003#{504be32c-ccf6-4d2c-b73f-6f8b3747e22b}\#\Device Parameters" -name "FriendlyName" -value "MOTU MIDI 2 Port 1"
Set-ItemProperty -path "$midiInHive##?#SWD#MMDEVAPI#MIDII_AD021E82.P_0003#{504be32c-ccf6-4d2c-b73f-6f8b3747e22b}\#\Device Parameters" -name "FriendlyName" -value "MOTU MIDI 2 Port 2"
Set-ItemProperty -path "$midiInHive##?#SWD#MMDEVAPI#MIDII_AD021E83.P_0003#{504be32c-ccf6-4d2c-b73f-6f8b3747e22b}\#\Device Parameters" -name "FriendlyName" -value "MOTU MIDI 2 Port 3"
Set-ItemProperty -path "$midiInHive##?#SWD#MMDEVAPI#MIDII_AD021E84.P_0003#{504be32c-ccf6-4d2c-b73f-6f8b3747e22b}\#\Device Parameters" -name "FriendlyName" -value "MOTU MIDI 2 Port 4"
Set-ItemProperty -path "$midiInHive##?#SWD#MMDEVAPI#MIDII_AD021E85.P_0003#{504be32c-ccf6-4d2c-b73f-6f8b3747e22b}\#\Device Parameters" -name "FriendlyName" -value "MOTU MIDI 2 Port 5"
Set-ItemProperty -path "$midiInHive##?#SWD#MMDEVAPI#MIDII_AD021E86.P_0003#{504be32c-ccf6-4d2c-b73f-6f8b3747e22b}\#\Device Parameters" -name "FriendlyName" -value "MOTU MIDI 2 Port 6"
Set-ItemProperty -path "$midiInHive##?#SWD#MMDEVAPI#MIDII_AD021E87.P_0003#{504be32c-ccf6-4d2c-b73f-6f8b3747e22b}\#\Device Parameters" -name "FriendlyName" -value "MOTU MIDI 2 Port 7"
Set-ItemProperty -path "$midiInHive##?#SWD#MMDEVAPI#MIDII_AD021E88.P_0003#{504be32c-ccf6-4d2c-b73f-6f8b3747e22b}\#\Device Parameters" -name "FriendlyName" -value "MOTU MIDI 2 Port 8"

Keep in mind that if you change port names, some apps may not recognize the port as belonging to the device they are looking for.