Blue-screen error message in Mqac.sys on Windows NT 4.0-based system

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Article ID: 306197 - View products that this article applies to.
This article was previously published under Q306197
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When you use Microsoft Message Queuing, your computer may quit (crash) with a blue-screen error in Mqac.sys.


When the Microsoft Message Queuing queue manager receives a packet and calls the driver to perform putpacket processing, an error in the putpacket processing operation causes the queue manager to free the packet, and then the driver attempts (unsuccessfully) to free the packet.


A supported fix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Apply it only to computers that are experiencing this specific problem. This fix may receive additional testing. Therefore, if you are not severely affected by this problem, Microsoft recommends that you wait for the next Windows NT 4.0 service pack that contains this fix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information about support costs, visit the following Microsoft Web site:;EN-US;CNTACTMS
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 typical 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 has the file attributes (or later) that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.
Date        Time    Version 	Size 	File name 
23-Sep-2002 08:51 	     	11,163 	Crdbsp7.sql 
23-Sep-2002 08:50 	    	19,968 	Mq2ndnd.exe 
02-Jul-2003 08:02 	61,584 	Mqac.sys 
23-Sep-2002 08:27 	34,064 	Mqcertui.dll 
02-Jul-2003 08:02 	34,064 	Mqdbmgr.dll 
02-Jul-2003 08:02 	59,152 	Mqdscli.dll 
02-Jul-2003 08:02 	56,592 	Mqdssrv.dll 
02-Jul-2003 08:02  227,088  Mqis.dll 
02-Jul-2003 08:02 	16,144 	Mqkeyhlp.dll 
02-Jul-2003 08:02  142,096  Mqoa.dll 
02-Jul-2003 08:02 	8,464 	Mqperf.dll 
02-Jul-2003 08:02  509,200  Mqqm.dll 
02-Jul-2003 08:02  110,352  Mqrt.dll 
23-Sep-2002 08:45 1,831,320 Mqsetup.dll 
02-Jul-2003 08:02 	14,096 	Mqsvc.exe 
02-Jul-2003 08:02  106,768  Mqutil.dll 
23-Sep-2002 08:27 	62,224 	Msmq.cpl 
The hotfix package for this article will actually contain the fix for the following article in the Microsoft Knowledge Base:
822835 MSMQ: Event ID 2085 "Unable to create message file ..."


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


Article ID: 306197 - Last Review: February 22, 2007 - Revision: 4.4
  • Microsoft Message Queue Server 1.0, when used with:
    • Microsoft Windows NT Server 4.0 Standard Edition
  • Microsoft Message Queuing 2.0, when used with:
    • Microsoft Windows NT Server 4.0 Standard Edition
kbhotfixserver kbqfe kbbug kbqfe KB306197

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