Avast BSOD on startup(aswMonFlt.sys)

system · 2017-05-09T22:38:33.000Z

Hi,
I’m using Win7, Avast Free. After recent update it constantly cause BSOD on windows startup, about some seconds after logon.
Accoring minidump it’s DRIVER_VERIFIER_IOMANAGER_VIOLATION on aswMonFlt.sys+1984
The safe boot mode on PC works normally.
The diagnostic boot+avast service only cause such error again.
I uninstall avast from safe mode, load windows in normal boot and installed avast again. It started right after install, but when I reboot the issue appears again.
I’ve checked PC from safe mode with such utilites as cureit, FRST or kaspersky virus removal tool and they can’t find anything suspicious.
What is aswMonFlt.sys module? What can be the BSOD cause? Driver conflict? Avast self-defence module? How to rid off that?
Thanks for any help

Asyn · 2017-05-10T03:23:54.000Z

Follow instructions: https://www.avast.com/faq.php?article=AVKB33#artTitle

Spec8472 · 2017-05-10T06:57:36.000Z

Please provide the minidump file.

AntonG post:1:

Hi,
I’m using Win7, Avast Free. After recent update it constantly cause BSOD on windows startup, about some seconds after logon.
Accoring minidump it’s DRIVER_VERIFIER_IOMANAGER_VIOLATION on aswMonFlt.sys+1984
The safe boot mode on PC works normally.
The diagnostic boot+avast service only cause such error again.
I uninstall avast from safe mode, load windows in normal boot and installed avast again. It started right after install, but when I reboot the issue appears again.
I’ve checked PC from safe mode with such utilites as cureit, FRST or kaspersky virus removal tool and they can’t find anything suspicious.
What is aswMonFlt.sys module? What can be the BSOD cause? Driver conflict? Avast self-defence module? How to rid off that?
Thanks for any help

system · 2017-05-10T10:59:01.000Z

Hi,
minidump file link: https://yadi.sk/d/pw2YHc5Y3HxJnx

Right now I have uninstalled avast to make computer boot on normal mode. Also chkdisk for errors, nothing found.

Chris414 · 2017-05-10T11:20:40.000Z

Just wanted to add an x2 to this. I’ll do what I can to pull the dump. I can’t take a chance of what happened before and take down my office staff. It’s getting disabled until I see more comments on this.

Spec8472 · 2017-05-10T11:45:52.000Z

This issues are caused solely by active driver verifier. It will be fixed in next version. In the meantime, please disable driver verifier (verifier.exe) checks, as it has very negative performance impact (not mentioning BSOD’s )

Active verifier flags in time of the dump creation:

Verify Flags Level 0x000009bb

STANDARD FLAGS:
(0x00000000) Automatic Checks
(0x00000001) Special pool
(0x00000002) Force IRQL checking
(0x00000008) Pool tracking
(0x00000010) I/O verification
(0x00000020) Deadlock detection
(0x00000080) DMA checking
(0x00000100) Security checks
(0x00000800) Miscellaneous checks

ADDITIONAL FLAGS:
(0x00000004) Randomized low resources simulation
(0x00000200) Force pending I/O requests
(0x00000400) IRP logging

[X] Indicates flag is enabled

system · 2017-05-11T01:30:35.000Z

Thanks, it helps to me. I disabled driver verifier and now system boots OK with avast.

system · 2017-05-11T14:15:25.000Z

Thank you Spec8472.

I experienced the same results as AntonG after updating to AVAST version 17.4.2294, on May 9th .
BSOD at start time: IO SYSTEM VERIFICATION ERROR in aswMonFlt. Sys – WDM Driver error 224.
Several uninstalling or new installing operations didn’t rid off.
I uninstalled AVAST.
I have tried to implement AVG software with the same problems.
BSOD at start time: IO SYSTEM VERIFICATION ERROR in AVGMonFlt. Sys – WDM Driver error ….
I also noticed a strange component asChLic.exe (from AVG Software) as if AVAST and AVG were sharing the same pieces of software!

I disabled VERIFIER list of driver verification, following Spec8472’s recommendation on May 10th.
Thank you Spec8472. All went well after a new installation of AVAST.

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