How can I access the Microsoft GS Wavetable Synth on Windows 8.1?

I'm writing a Web MIDI application (in Javascript) using the Web MIDI API.

Neither Jazz nor the Chrome Web MIDI implementation are finding the Microsoft GS Wavetable Synth on my Windows 8.1 laptop.
Using the same web page, there's no problem on my Windows 7 machine.

A Chrome engineer says: "Chrome just uses aka winmm to control MIDI devices under Windows. I guess the GM synth is not exposed to the API any more, and DXi support is needed to use it.".
The author of Jazz says: "It works fine on my Windows 8 machine". (As I said, its not working on my Windows 8.1 machine.)

I'm told (ultimately by a Yamaha engineer) that the MS GS Synth gets locked if it is accessed by another program first.
Windows Media Player is playing MIDI files okay on my W8.1 machine, so the MS GS Synth is there somewhere.
I tried disabling Windows Media Player and restarting without it. But the problem persists.
I've also tried disabling all the startup processes in the Task Manager, and restarting, but that does not help either.
Where do I go from here?

All the best.


Question Info

Last updated March 30, 2019 Views 4,405 Applies to:


Thank you for the Update on this issue.

If you are suspecting that Windows Components might be corrupted then I recommend you to go through the following methods:

Method 1:

System File Checker is a utility in Windows that allows users to scan for corruptions in Windows system files and restore corrupted files.


1. Swipe in from the right edge of the screen, and then tap Search. Or, if you are using a mouse, point to the lower-right corner of the screen, and then click Search.

2. Type Command Prompt in the Search box, right-click Command Prompt, and then click Run as administrator.

3. If you are prompted for an administrator password or for a confirmation, type the password, or click Allow.

4. At the command prompt, type the following command, and then press ENTER:

 sfc /scannow

5. After the process is finished, you may receive one of the following messages:


Windows Resource Protection did not find any integrity violations.

Windows Resource Protection could not perform the requested operation.

Windows Resource Protection found corrupt files and successfully repaired them.

Windows Resource Protection found corrupt files but was unable to fix some of them.


Method 2:


After performing SFC scan, I suggest you to Fix Windows corruption errors by using the DISM or System Update Readiness tool.


Refer you to the Link:


DISM or System Update Readiness tool


Once you complete both the steps then please try to install Windows Update.


Following are the steps to install available Windows Updates.


  1. Press Windows + R, type control.exe and push ok.
  2. Type Windows Update in the Search box, then click Windows Update in the results pane.
  3. Click Check for Updates. After the scan is complete, click Review optional updates.
  4. Click the check box next to the updates, then click Install updates.
  5. If prompted, review the license agreement, then click I Accept.
  6. Follow the onscreen instructions to download and install the updates. If prompted, reboot your computer.


After installing all the pending updates, please try to run DISM Windows image scan and restore health command.

Following are the steps:


  1. Press Windows + X, select Command Prompt (admin).

  2. Type, “Dism /Online /Cleanup-Image /CheckHealth” (without quotes) and push Enter.

  3. After completion type, “Dism /Online /Cleanup-Image /ScanHealth” (without quotes) and push Enter.

  4. After completion type, Dism /Online /Cleanup-Image /RestoreHealth” (without quotes) and push Enter.

  5. When finished, it is recommended to restart the PC to configure any updates that may have been affected by this.


If issue still persists please reply with the details of the troubleshooting steps with the result.


Hope the information helps. Let us know if you need further assistance with Windows related issues, we’ll be glad to assist you.


Shivam Kesarwani

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