I originally reported this problem inadvertently in the Business Protection section of the forum - it was the first in a series of related threads that WhoCrashed gave a link to.
http://forum.avast.com/index.php?topic=108689.0
Since I am using the free version of Avast anti-virus, I thought it best to post here, also.
To summarize; since upgrading from XP Pro SP3 to Win-7 64-bit ten days ago, I have experienced no less than 5 blue-screen crashes where the Avast virtualization driver has been identified as the cause. The crashes always occur at Windows log-in. Screen image first freezes with scrambled horizontal lines, then blue-screen, closedown, reboot.
The first time it happened I did a clean install of Win7. The WhoCrashed report of the 4 instances that have occurred since (the last this morning) is below.
From the many similar reports I’ve come across on this and other computing forums, it would appear that this is a well known and long-standing problem for which no fix has been provided. Surely, with all of the memory dumps that have been uploaded to Avast, they could have resolved the problem by now. One of the reasons I upgraded to Win 7 instead of Win 8 was because I had reasonably assumed that any third party software issues with Win 7 would have been long ironed out.
Having been a long time user of Avast AV, and encountering no such problems when running XP Pro Sp3 (including this same PC that I am now running Win 7 on), I was actually considering upgrading to the paid version. But in view of this BSOD issue, I’m about ready to ditch Avast. Shame, as in all other respects I really like it.
WhoCrashedReport:
computer name: XXXXXXXXXXXXX windows version: Windows 7 Service Pack 1, 6.1, build: 7601 windows dir: C:\Windows Hardware: ASUSTeK Computer INC., M5A78L-M LX PLUS CPU: AuthenticAMD AMD FX(tm)-6300 Six-Core Processor AMD586, level: 21 6 logical processors, active mask: 63 RAM: 4007780352 total VM: 2147352576, free: 1929662464
Crash Dump Analysis
Crash dump directory: C:\Windows\Minidump
Crash dumps are enabled on your computer.
On Sun 12/29/2013 2:08:02 PM GMT your computer crashed
crash dump file: C:\Windows\Minidump\122913-17643-01.dmp
This was probably caused by the following module: ntoskrnl.exe (nt+0x75BC0)
Bugcheck code: 0x3B (0xC0000005, 0xFFFFF80002BA3C4A, 0xFFFFF88008FC75E0, 0x0)
Error: SYSTEM_SERVICE_EXCEPTION
file path: C:\Windows\system32\ntoskrnl.exe
product: Microsoft® Windows® Operating System
company: Microsoft Corporation
description: NT Kernel & System
Bug check description: This indicates that an exception happened while executing a routine that transitions from non-privileged code to privileged code.
This appears to be a typical software driver bug and is not likely to be caused by a hardware problem.
The crash took place in the Windows kernel. Possibly this problem is caused by another driver that cannot be identified at this time.On Sun 12/29/2013 2:08:02 PM GMT your computer crashed
crash dump file: C:\Windows\memory.dmp
This was probably caused by the following module: aswsnx.sys (aswSnx+0x27E48)
Bugcheck code: 0x3B (0xC0000005, 0xFFFFF80002BA3C4A, 0xFFFFF88008FC75E0, 0x0)
Error: SYSTEM_SERVICE_EXCEPTION
file path: C:\Windows\system32\drivers\aswsnx.sys
product: avast! Antivirus
company: AVAST Software
description: avast! Virtualization Driver
Bug check description: This indicates that an exception happened while executing a routine that transitions from non-privileged code to privileged code.
This appears to be a typical software driver bug and is not likely to be caused by a hardware problem.
A third party driver was identified as the probable root cause of this system error. It is suggested you look for an update for the following driver: aswsnx.sys (avast! Virtualization Driver, AVAST Software).
Google query: AVAST Software SYSTEM_SERVICE_EXCEPTIONOn Tue 12/24/2013 7:38:30 PM GMT your computer crashed
crash dump file: C:\Windows\Minidump\122413-25334-01.dmp
This was probably caused by the following module: ntoskrnl.exe (nt+0x75BC0)
Bugcheck code: 0x3B (0xC0000005, 0xFFFFF800029B0B05, 0xFFFFF8800794EE80, 0x0)
Error: SYSTEM_SERVICE_EXCEPTION
file path: C:\Windows\system32\ntoskrnl.exe
product: Microsoft® Windows® Operating System
company: Microsoft Corporation
description: NT Kernel & System
Bug check description: This indicates that an exception happened while executing a routine that transitions from non-privileged code to privileged code.
This appears to be a typical software driver bug and is not likely to be caused by a hardware problem.
The crash took place in the Windows kernel. Possibly this problem is caused by another driver that cannot be identified at this time.On Tue 12/24/2013 3:47:34 AM GMT your computer crashed
crash dump file: C:\Windows\Minidump\122313-24367-01.dmp
This was probably caused by the following module: ntoskrnl.exe (nt+0x75BC0)
Bugcheck code: 0x18 (0x0, 0xFFFFFA80051EA8E0, 0x2, 0xFFFFFFFFFFFFFFFF)
Error: REFERENCE_BY_POINTER
file path: C:\Windows\system32\ntoskrnl.exe
product: Microsoft® Windows® Operating System
company: Microsoft Corporation
description: NT Kernel & System
Bug check description: This indicates that the reference count of an object is illegal for the current state of the object.
This appears to be a typical software driver bug and is not likely to be caused by a hardware problem. This might be a case of memory corruption. More often memory corruption happens because of software errors in buggy drivers, not because of faulty RAM modules.
The crash took place in the Windows kernel. Possibly this problem is caused by another driver that cannot be identified at this time.
Conclusion
4 crash dumps have been found and analyzed. A third party driver has been identified to be causing system crashes on your computer. It is strongly suggested that you check for updates for these drivers on their company websites. Click on the links below to search with Google for updates for these drivers:
aswsnx.sys (avast! Virtualization Driver, AVAST Software)
If no updates for these drivers are available, try searching with Google on the names of these drivers in combination the errors that have been reported for these drivers and include the brand and model name of your computer as well in the query. This often yields interesting results from discussions from users who have been experiencing similar problems.
Read the topic general suggestions for troubleshooting system crashes for more information.
Note that it’s not always possible to state with certainty whether a reported driver is actually responsible for crashing your system or that the root cause is in another module. Nonetheless it’s suggested you look for updates for the products that these drivers belong to and regularly visit Windows update or enable automatic updates for Windows. In case a piece of malfunctioning hardware is causing trouble, a search with Google on the bug check errors together with the model name and brand of your computer may help you investigate this further.