The midi…midi9 entries in the Drivers32 location in the registry come up often, especially in the context of certain brands of drivers, like Korg.
Location for 64-bit apps
Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Drivers32
Location for 32-bit apps
Computer\HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows NT\CurrentVersion\Drivers32
This has led to the idea that Windows only supports 10 MIDI devices. In reality, it’s only 10 drivers which require their entries in the registry.
Some tools, driver uninstallers, and entry reordering tools, can break this location in the registry. For example, they can create an incorrect midi0 entry when the first entry needs to be named midi not midi0.
With Windows MIDI Services, these tools can also remove the necessary entries which make Windows MIDI Services work.
Windows MIDI Services does not load drivers from the registry. Instead, it relies on the two midiN entries and ignores the remainder. You no longer need to ensure other drivers are listed within the 10 entries.
These entries are used in the 32-bit and 64-bit registry locations.
| Entry | Type | Value | Description |
|---|---|---|---|
midi |
String | wdmaud.drv |
This is required for loading the in-box MIDI synthesizer |
midi1 |
String | wdmaud2.drv |
This sends control of the rest of enumeration to the midisrv service. |
In addition, these values are used only in the 64-bit registry location.
| Entry | Type | Value | Description |
MidisrvTransferComplete |
DWORD | 1 |
Indicates that AudioEndpointBuilder should not enumerate MIDI devices. Instead, the Windows MIDI Service will handle that. |
UseLegacyMidi |
String | 0=use midisrv, 1=use legacy, 2=hybrid (not recommended) | Optional and defaults to 0 if not specified. |
The MIDI Settings app has a feature on the troubleshooting page which can be used to fix these registry locations.
Windows MIDI Services is now fully multi-client, which was one of the primary reasons to use vendor drivers for otherwise class-compliant MIDI devices. We recommned that you not install third-party drivers unless necessary.
Windows MIDI Services is an open source project with all source available on GitHub. We have a great community on Discord as well. Between GitHub and Discord, you should find the information you are looking for.
