Loop Midi hidden in Windows 11 25H2 fix

OK1 · February 23, 2026, 3:15am

I’m running Windows 11 24H2 - 26100.7840, and a few days ago noticed that Loop Midi Ports were not being recognised by other apps.

In my config :

TotalKeyMix (“a keyboard to MIDI” app for controlling volume via MIDI control events, using keyboard strokes) sends MIDI to a LoopMidi port.
LoopMidi receives and forwards to upstream apps such as my DAW - Reaper.

Normally the startup sequence is -

Start LoopMidi,

Start TotalKeyMix.,

Start Reaper.

Reaper could also NOT “see” my MIDI Controller Keyboard (A Yamaha CP33 which connects via USB) and could not “see” the LoopMidi port.

TotalKeyMix was not “seeing” the LoopMidi Ports, created by LoopMidi.

So I searched and found this thread.

The workaround/solution at the start of this thread, solved my issues.

Start LoopMidi - and it creates whatever ports you have configured.
Stop the Windows Midi Service as directed at the start of this forum thread
Start the Windows Midi Service as directed at the start of this forum thread.
(please do not use restart. Stop and Start the service. For some reason, restart did not work)
Then start any other apps which are sending to or receiving from LoopMidi MIDI ports.

The challenge is the randomness of this issue, it does not occur consistently, when Windows starts up. Well at least one has a workaround now. And one does not know if the LoopMidi ports are initialised, except one starts up a MIDI app, and discovers something is not quite right.

Psychlist1972 · February 23, 2026, 4:07am

The loopMIDI issue will be fixed. I have it mostly fixed, just working on issues with > 16 loopMIDI ports right now.

In the meantime, I’ve put out a preview (on our Discord server) of MIDI 1.0-style loopback endpoints for people who need the input and output to have exactly the same name.

Info here

github.com/microsoft/MIDI

[Feature] Simple MIDI 1.0 loopback ports

opened 07:37PM - 20 Feb 26 UTC

melanchall

feature request

fixed-awaiting-public-release

**Is your feature request related to a problem? Please describe.** Copied from …#844. I'd like to ask you to consider add possibility of MIDI 1 unidirectional loopback devices creation. Why? Many people use software like loopMIDI, loopBeX and so on for years where you name a virtual port and get a pair of input/output devices with that name. If new bidirectional MIDI 2 loopback devices is the only option, it will just break experience of many users. Event sent to A out endpoint will be received on B in endpoint and vice versa... That won't be obvious for them I believe. So why do not just provide two options for loopback/virtual devices: 1) unidirectional MIDI 1 without name modifications; 2) bidirectional MIDI 2 with A/B endpoints different naming? I'm sure and I see that you care a lot about users of new MIDI services and about their pain. And I'm sure MIDI 1 option will be much popular because from my experience MIDI 1 covers 95% user cases. The same is for API. I mean virtual devices. In CoreMIDI on macOS users have a choice what type of endpoints to create: MIDI 1 or MIDI 2. And it's pretty straightforward to create virtual MIDI 1 in/out pair. Of course you can create four endpoints and wire them as you want. So I just ask to pay attention to scenario that exists for many many years and will be popular many years further. MIDI 2 is a great standard but it's required for not so many people. You can argue with me because you have much more experience in MIDI/audio and music at all. I just want everyone to be comfortable with new MIDI API. **Describe the solution you'd like** MIDI Console app parameter/PowerShell cmdlet. **Describe alternatives you've considered** – **Do you wish to contribute a solution?** No **Additional context** –

Pete
Microsoft

OK1 · February 23, 2026, 4:46am

Hi Pete, what would we do without you. I recalled your name from gear space dot com. Good to have you here.

I just installed the SDK and Midi Settings App. It was not too much of a big deal, in my case to understand and appreciate that, at this time, the loopback input and outputs need to be named differently. i.e if I send to A, I receive on B.

Just tested this out, and its working ok. Sadly that negates the need for LoopMidi, at least for me. So in a way, my workaround at this time, is to use the default loopback, provided by the SDK.

TotalKeyMix translates keyboard keystrokes into MIDI commands, sends these to the default loopback A port, and Reaper DAW receives on default loopback B port.

For me, I prefer it this way. In my head, I know Output Port = A. Input Port =B.

In my case it’s not an issue cos I’m not sending anything the other way, from B to A.

I can imagine possibly scenarios where it may be useful to have the loopback pair have the same name.

Anyway - thanks. I find the monitor tools, in the Microsoft MIDI app, useful. Really helped diagnose and confirm things were going in the right direction.

Had to restart the MIDI services, via the MIDI app, which was convenient, when Reaper could no longer “see” my Yamaha CP33 Midi Port - Connected via USB MIDI. Restarted Reaper after restarting MIDI servives, and all is fine now.

Especially glad to see Microsoft stepping up, and supporting MIDI in this way. MIDI App, man I must say though, no fault of yours, but that was a LLLLLLOOOOOONG TIME coming. At least 2 or 3 decades. Maybe there have been MIDI tools, in previous SDKs, which I would not know about, but certainly it would be wonderful to have this MIDI tool, in a future Windows update, as part of the OS proper.

Thanks for your support. We value your contribution to our ambitions, with Windows. Best wishes.

When you retire from Microsoft, they had better have replacements.

Keep well and thanks

K.

Psychlist1972 · February 23, 2026, 5:57am

Thanks. We’ll end up keeping both types of loopback ports: The bidirectional MIDI 2.0 style, and the simpler MIDI 1.0 style. Each are usable for different scenarios.

The first round of bug fixes from the January rollout will start going out later this week. That won’t include the loopMIDI fix, but will include some around apps not being able to detect a newly plugged-in device after they start (if they were able to before this update).

There have been some crazy things we found in this rollout. For example, multi-client is the single most requested feature. Folks want ports to be usable by more than one app. Well, that broke some apps which were using the error returned when opening a port to know that they’ve already opened it. So they just looped through opening every port millions of times.

Another is related to SysEx transfer. The new MIDI stack is much faster so we’re seeing cases where apps were allocating MIDI buffers after making a call, not before, and so were not receiving the SysEx data. We have a workaround for that coming in next month’s fixes.

(The loopMIDI bug is 100% my code and my bug, though. I’m working on it)

Pete
Microsoft

TabSel · February 25, 2026, 7:04am

might be an edge case here, as I’m using dozens of LoopMIDI and rtpMIDI ports with BOME MIDI Translator across a three computer setup to work around some midi devices offering single client ports, having BUSes of ALL studio devices on ALL machines etc…

It currently is annyoing as hell. I dont want to shut down my machines anymore knowing what hassle it will be getting everything set up and working again after rebooting. Close all autostart apps, wait for loopmidi/rtpmidi to start/run, restart midisrv, restart apps in correct order to recognise midi ports etc…

I dont want to use the new loopback midi ports (A/B) as this will double my already enstensive midi port setup and I’d have to rebuild my BOMEMIDITranslator routing setup.
This new stack came a huge suprise to me. Everything worked like a charm for years. Suddenly it broke my studio setup without me knowing why. The time spent for investigatinh what was going on alone… man…

I understand the motivation behind it all, but come on…

is there any time schedule for everything working again as it was, please, or should I invest the time rebuilding my midi setup from scratch?

Johnny_Moneto · February 25, 2026, 8:34am

Can’t you just roll back in order to get a working setup again?

Home_Studio_87 · February 25, 2026, 10:45am

You can delete the windows update “KB5074105” and wait for a fix that may come in march….

Nemanja86 · February 25, 2026, 12:00pm

@Psychlist1972 Please, can you tell me, is KB5077241 optional update worth it since i don’t see any mention of MIDI 2.0 on the list?

Thanks!

Psychlist1972 · February 25, 2026, 3:23pm

I was just coming here to post this:

Our 2D “4th week of February” fixes are going out this week. For MIDI, that includes:

Apps not getting an updated device count when you go from 0 connected MIDI devices to 1 connected MIDI device. Apps that used to be able to detect a new device added before the new MIDI stack will be able to do that again
Some lock-ups with device removal and sending to disconnected devices

These fixes use the same process to roll out, which means the fix may be applied any time up to 30 days after you install the KB. I don’t have any way to tell you if the update is enabled or not on your PC after you install it.

Pete
Microsoft

Nemanja86 · February 25, 2026, 5:22pm

Thanks Pete!

I’ve installed it and nothing changed, it was worth trying.

Btw, to anyone using Sideshowfx profiles, i found a simple workaround. Just make a simple one page profile for Streamdeck with classic key commands and add icons from profile pack they provided, so you can have a minimal setup until Windows MIDI is fixed.

Cheers!

tremolux · February 25, 2026, 8:31pm

thats what I did!
Have a bigger live stream event tomorrow and needed a quick solution to get my streamdeck back working with Cubase and loopMidi.
So I performed a win rollback - the win update came in this morning.
Things are working now!
I will update and check for a loopMidi solution next week.

arbibarbarona · February 26, 2026, 8:29am

Hello,

While the MIDI 2.0 rollout is currently affecting the LoopMIDI port, the SideshowFX Cubase Pro Pack download includes a profile designed for Cubase 11. This profile relies entirely on hotkeys, as MIDI Remote was not available at that time.

When loaded together with the corresponding keyboard preset, it works across all Cubase versions, including Cubase 15. However, newer features introduced in later versions are not implemented, since the profile was originally built for Cubase 11.

This serves as a temporary solution until the MIDI issue is resolved.

Cupboardy · February 26, 2026, 7:07pm

Run into this problem today, with my Streamdeck using LoopMIDI. Stopping and starting the MIDI services hasn’t worked for me. Not read through the whole thread yet, will try any other suggestions.

Just to add: Since the Win 12 update, Cubase has started to mass duplicate MIDI remote devices for some reason. When I open the lower zone to view devices, there’ll be 5 or more of same device?

Psychlist1972 · February 26, 2026, 7:27pm

There’s also a preview of a built-in MIDI 1.0-style loopback transport in our Discord server. That includes a service plugin for the transport itself, and the client tools to manage those endpoints.

Folks have been finding they work well to replace loopMIDI.

Bonus, they are implemented in the service, so no kernel transitions, no driver installation, no order of startup issues, and they will work on Arm64 PCs.

https:://aka.ms/mididiscord

Thread:

Screenshot from customer

I’ll put that preview out on GitHub likely this weekend or next week at the latest. It’ll make it into Windows around the same time as the loopMIDI fix later this spring.

Pete
Microsoft

tremolux · March 2, 2026, 8:39am

@Psychlist1972

Is there a guide how to setup a Streamdeck - Cubase connection by using Midi 2.0 endpoints? I just tried this and I cant get it to work.
I installed
“Windows.MIDI.Services.Basic.MIDI.1.0.Loopback.Preview” (restarted)
and “Windows.MIDI.Services.SDK.Runtime.and.Tools.1.0.16-rc.3.3-x64.exe”
In the windows Midi and musicians settings I created some Midi 2.0 loop endpoints
I see and select them as midi ports in my streamdeck settings
I created a new Streamdeck controller setup in Cubase .
But still I get the yellow exclamation mark (fail alert…) when im pressing the assigned streamdeck button.
Looking for some ideas now.
A guide would be super helpful.

pavlii · March 2, 2026, 11:42pm

Just a question: we will not need anything like MIDI loopback application to be able to run another (let’s say MIDI-OX) application in parallel with Cubase? I mean we should not get the error message related to “port already used by another app…”. Correct?

Thnx for answer and your activity, Pete!

P.

Psychlist1972 · March 3, 2026, 12:29am

Correct.

Pete
Microsoft

Psychlist1972 · March 3, 2026, 12:34am

Use the MIDI 1.0 loopbacks you had installed in that preview.

Otherwise, you need to use the loopbacks like they are in the diagrams and explanations when created.

Bidirectional MIDI 2.0 loopback

Basic MIDI 1.0 loopback

Use these to replace loopMIDI-style loopbacks

I had planned to put out a video explaining how to use them, but I’ve been straight out working with folks to get past driver crashes etc. so haven’t gotten to it yet.

Additionally, we have a beta-level preview of the fixes to the service to support loopMIDI, rtpMIDI etc. It’s on the Discord server-only for now.
Windows MIDI / Audio and see the #early-preview-releases channel

Pete
Microsoft

pavlii · March 3, 2026, 6:50am

Thanx a lot for the info Pete! Crossing fingers to all yours activities in the MIDI issues.

Regards, Pavel

damien.thonnard553 · March 5, 2026, 4:59pm

Thank you so much for this !!! I’ve been struggling with this for hours not understanding why this wouldn’t work.