No Sound, Program Hangs, or Computer Becomes Unstable When You Play MIDI Files with SYSEx Messages (304435)


The information in this article applies to:

  • Microsoft Windows Millennium Edition
This article was previously published under Q304435
IMPORTANT: This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows Registry

SYMPTOMS

When you play a MIDI file that contains SYSEx messages on a computer that has Windows Driver Model (WDM) audio drivers and uses the GS Wave Table Synthesizer, you may experience one or more of the following symptoms:
  • The MIDI file may not play.
  • The program you use to play the MIDI file may stop responding (hang).
  • Your computer may become unstable after you use the End Task feature to quit the program you used to play the MIDI file.

CAUSE

This problem can occur if a timing problem causes the WDM audio drivers to wait for the MIDI output to complete.

RESOLUTION

WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that this article describes. Apply it only to systems that are experiencing this specific problem.

To resolve this problem, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=support

Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

The English version of this fix should have the following file attributes or later:
   Date         Version      Size     File name 
   ---------------------------------------------
   Sep-27-2001  4.90.0.3002  100,496  Wdmaud.sys


After you install the hotfix, enable it with a registry setting. To do so, use Registry Editor (Regedit.exe) to locate the following key in the registry:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\wdmaud

Add a new DWORD value to this registry key, and then quit Registry Editor:

Value name: Enable Q304435
Data type: DWORD
Value data: 1

WORKAROUND

To work around this problem:
  1. Click Start, point to Settings, click Control Panel, and then double-click Multimedia.
  2. Click the MIDI tab.
  3. Under Single Instrument, click a device other than the Microsoft GS Synthesizer, and then click OK.

STATUS

Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.

MORE INFORMATION

The Microsoft GS Wavetable Synthesizer (Swmidi.sys) is only used if you are using a WDM audio driver.

A common scenario under which this problem occurs unexpectedly is when you are using Microsoft Internet Explorer to open a Web site that contains an embedded MIDI file that contains SYSEx messages.

For additional information about Windows Me hotfixes, click the article number below to view the article in the Microsoft Knowledge Base:

295413 General Information About Windows Millennium Edition Hotfixes

Modification Type:MinorLast Reviewed:10/18/2005
Keywords:kbHotfixServer kbQFE kbenv kbprb kbQFE KB304435
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