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What is 'mwac.cat'?

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For some time now (don't know when it started), I get this warning in Win log:


Event Time    Record ID    Event ID    Level    Channel                                                                        Provider   
07.03.2019       11308       3010    Warning    Microsoft-Windows-CodeIntegrity/Operational    Microsoft-Windows-CodeIntegrity


Description                                                                             Opcode    Task    Keywords                           User  

Der mwac.cat-Katalog konnte nicht geladen werden.    100              2        0x8000000000000000    NT-AUTORITÄT\LOKALER DIENST    


I can find 'mwac.cat' in 'C:\Program Files\Malwarebytes\Anti-Malware\sdk' and in 'C:\Windows\System32\catroot\{F750E6C3-38EE-11D1-85E5-00C04FC295EE}'.

Is this warning coming from Malwarebytes? And if so, what has to be done?


Win 7 Pro SP1 64-bit,  Malwarebytes Premium, Malwarebytes WFC


Best Regards,



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MWAC is Malwarebytes Web Access Controller which is what Malwarebytes uses for the Web Protection component in Malwarebytes (bad website blocking).  It relies on the Windows Filtering Platform (WFP) APIs in modern versions of Microsoft Windows which is the same infrastructure/APIs used for the built in Windows Firewall in Windows Vista and newer Windows versions.

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thanks for your fast responses. After having read the info about mwac.sys (the link posted by MAM), I searched for this driver, but could not find it on the OS drive. After that, I searched for mwac.cat again, and it was not found on the locations I found them previously. This is a bit strange. I am no Windows Pro, but after exile360 mentioned the WFP, I come to suspect that it might have something to do with the 'new' MB WFC (formerly known as 'Binisoft WFC')...

I will have an eye on this, but otherwise ignore it.


Thanks and Best regards,




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I have Premium installed (please see my initial post). However, I only start it up when needed, it is not my primary malware software. When MB starts up, it creates the sys and the cat files; when it is shut down, it deletes these files.

Maybe WFC detects that MB is installed and wants to access the cat file, but MB is shut down at that time, so the cat file does not exist.




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Yes, that's normal.  Malwarebytes creates its drivers and loads them as needed when protection loads and removes them when they are not active so that you get the best performance when you terminate a protection component or exit Malwarebytes completely rather than leaving them loaded silently in memory as some products do.

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