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(old) In-box Dev (and Advanced Customers) Preview 6
Pre-release
In-Box Developer and Advanced/Technical Customer Preview 6
UPDATE 2026-09-03: New tools package. See below.
UPDATE 2026-09-02: Updated Network MIDI 2.0 and Bluetooth MIDI apps. Uninstall previous versions and install the new versions in the assets below.
This release is for developers and technical customers with an interest to test, file bugs, and provide feedback. There are almost certainly bugs and missing/incomplete features. Do not install anything unless you have read this entire release notes and are comfortable with what is here.
We're quickly coming up on the deadline to get fixes and features into the November release. While we continue testing and debugging here, I wanted to get this out to you now for your own development and testing. Plan is to have all of these transports and the API in Windows 11 25h2 and higher starting during the last week of November 2026.
Permitted Use
We want to ensure customers have the best experience going forward. Because of this, we want to ensure that these app-local binaries are not present on customer systems which have the binaries in System32. There is nothing in these binaries to enforce this, so it is entirely on you, the app or library developer, to ensure you do not distribute these files in situations where that happens.
"Binaries" here refers to the .dll, .pri and .pdb files included in the packages below, as well as any tool .exe files included.
"Product" here refers to your application, library, service, or other code you are writing against these files
| Use | Notes |
|---|---|
| Development | Your developers may use the binaries here for development and testing of future releases of a product |
| Testing | Your testing team(s) may use these binaries with your product |
| Customer Preview | You may distribute the WinRT API binaries with an alpha/beta/preview version of your app as long as that app has an enforced (through code or obvious and explicit agreement) expiration date of no later than January, 15, 2027, and you clearly indicate that this is using pre-release code which may not work in production. You are responsible for all support |
| Production / Release app | These WinRT API binaries are not permitted for this use. Do not distribute these binaries with a production application unless you have received explicit emailed permission from Pete Brown at Microsoft. |
Do not redistribute any of the installers or transports.
Breaking API Changes
Fixed a few broken UUIDs
MidiLegacyPortDeviceInformation had an auto-generated static interface id
IMidiServiceConfigResponse had an incorrect interface id
Network MIDI 2.0
As with the previous release, delete all Network MIDI 2.0 entries from your midiconfig json file, or simply delete the configuration file and re-create it. There are a few breaking changes in there now.
Update 2026-08-31: There's a PowerShell script in the assets that can do this work for you now, repairing or removing the entries.
mDNS Watcher
The mDNS / DNS-SD device watcher needed rebuilding from the ground up using base Win32 APIs. As a result, it is no longer backed by a WinRT Device Watcher, but still retains the same shape. Threading may be slightly different.
Why? The DNS-SD implementation in the base WinRT Device Watcher does not actually fire Updated or Removed events. It also returns null for the TTL property, and has no other presence indicator. To the best of my knowledge, this limitation is not documented.
Included Transports
This includes three transports which, assuming they meet the quality gates, will ship in the November release. This also includes the WinRT API expected to ship at the same time.
The main application is the new MIDI Settings app. However, it looks completely different from the one you are used to. This is a new C++ app that starts faster and includes fewer features directly in the app. Here are all the GUI apps included
Important Bluetooth Consideration
The Bluetooth MIDI 1.0 transport is new. Please be sure to report any bugs. Do note that if you have paired a BLE MIDI device, it will likely be picked up by our old BLE MIDI 1.0 support in WinRT MIDI 1.0, resulting in the device not coming up on the new transport. You can usually get around this by unpairing the device, or if that is not possible, by deleting the paired BLE device from the Sound, video and game controllers section of Device Manager. Once this transport is in production on Windows, this will not be an issue.
If you are using the KORG BLE MIDI 1.0 driver, fully and completely uninstall it before trying to use BLE MIDI 1.0 devices.
Devices successfully tested so far: See #1173
Network MIDI 2.0 Note
The Network MIDI 2.0 implementation is feature complete for our first in-box release. Note that it does not yet support any sort of authentication, and will not in our first in-box release.
MIDI 2.0 Loopback Note
The currently in-box Loopback transport does not support all the features used by the app (muting, listing, etc.). For that reason, you will not be able to properly configure MIDI 2.0 loopbacks with these tools until those features ship in Windows. Existing MIDI 2.0 loopbacks in your config file will continue to work as before.
MIDI 1.0 Loopback Note
Please be sure to follow the instructions below to ensure you using the MIDI 1.0 Basic Loopbacks from this release so all features are enabled.
Included Apps
The existing MIDI Settings app has been broken apart, rewritten in C++, and made easier to use. There are dedicated apps for specific setup steps for individual transports, and the main MIDI Settings app focuses on the management of endpoints and global settings. Most debugging and troubleshooting steps have been moved to the troubleshooting app. The apps no longer rely on the console tools.
Most extra endpoint detail has been moved out of the MIDI Settings app, but retained in the technical-focused MIDI Console. That is a deliberate choice to simplify the user experience.
All of the apps have settings for background color and style, and can be customized to your preferences.
There's continued fit & finish work going on in these apps, so please only report functional / stability bugs.
MIDI Settings
This is the primary app for MIDI. From here, you can access all of the other apps. It is deliberately simplified from the previous version.
IMPORTANT NOTE: Individual MIDI 1.0 port renaming is not in this app currently. It will be in the production release. Otherwise, this app has all the intended features.
MIDI Loopback Setup
Use this app for setting up MIDI 1.0 and MIDI 2.0 Loopbacks
MIDI Network Setup
Use this app to set up Network MIDI 2.0
MIDI Bluetooth Setup
Use this app to set up Bluetooth LE MIDI 1.0. Unlike the old BLE MIDI 1.0 support, most devices do not need to be paired to function. Additionally, other BLE MIDI 1.0 devices which simply didn't work with Windows (like some ROLI products) now work.
MIDI Monitor
MIDI Monitor shows you the MIDI messages arriving from a keyboard, controller, synth, or any other MIDI device on your PC. It’s the tool to reach for when you want to answer questions like “is this knob actually sending anything?”, “which channel is my keyboard on?”, or “what exactly does my synth send when I press that button?”.
MIDI SysEx Utility
The MIDI SysEx Utility sends System Exclusive files to an instrument and captures System Exclusive data coming back from one. Although not intended to be a fully-featured librarian, it covers most of what people mean by “patch librarian” jobs: loading a bank of sounds you downloaded, backing up the sounds you’ve made, applying a firmware update, or capturing a dump to send to a manufacturer’s support desk.
MIDI Scratch Pad
MIDI Scratch Pad lets you type MIDI messages yourself and send them to a MIDI device. It’s the tool to reach for when you want to answer questions like “does this synth actually respond to that controller?”, “what does this SysEx message from the manual do?”, or “can I reproduce that bug with one message?”.
MIDI Troubleshooting
This is where diagnostics, repro logging, and information about service health are all homed now. This is also where you'll find the tools to repair any registry damage, change drivers, change midisrv startup, or change the API Mode.
MIDI Troubleshooting App Overview
(Note: Wrong dates/time will be shown on the Sessions page until after the November CFR is enabled)
Install Instructions
As in the past, these previews are not signed and require you to turn on Developer Mode in Windows Settings > System > Advanced. They also require you to accept a few SmartScreen prompts and choose "keep" so the downloads are not automatically deleted. If you use third-party anti-virus / anti-malware software, it may also delete the installs after they happen. You'll need to refer to your own software's settings.
Minimum OS version: Windows 11 25h2.
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Make sure you have read all of the information above. Do not install anything without reading and understanding what is in this release.
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Before installing anything, completely uninstall all previous Loopback previews, network previews, and SDK Runtime and Tools packages. Uninstall the previous developer in-box previews. Ensure that your
Program Files\Windows MIDI Servicesdirectory is empty or missing and delete it if not. -
Install the Basic Loopback, Network, and Bluetooth transport packages. The order is not important.
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Install the Tools package.
Firewall
If you are using Network MIDI 2.0, you will need to let the MIDI Service through the firewall. Additionally, you will need to let the Network MIDI 2.0 Setup app through the firewall (it will prompt on first use).
https://microsoft.github.io/MIDI/kb/network-midi-firewall/
If you are using a third-party firewall product, please refer to their instructions. Both the app and the service need access.
Updates
UPDATE 2026-09-02: Updated Network MIDI 2.0 and Bluetooth MIDI apps. The Network MIDI app had an access violation when creating a host, which is fixed in this update. If you have the previous ones installed, uninstall previous versions and install the new versions in the assets below.
UPDATE 2026-09-03: Minor bug fixes to the in-box apps, plus a new preview MIDI Keyboard app. Note that the MIDI Keyboard app uses one of two connection options. When used in Virtual Device mode, it will lock up the service due to the existing Virtual Device bug (fixed for November, but not public yet.). Uninstall older 0.99.63 Tools package before installing this new 0.99.64 version. No API changes.