Windows 7 Updates destroy MBR

After a lot of tests it is obvious that at least one of the latest following Windows 7 updates destroys the MBR of the Hard Drive. It is up to Microsoft to help make explanations and to withdraw it.
KB890830
KB915597
KB3013455
KB3023562
KB2952664
KB3004394
KB3006137
KB3021917

My wife updated her Windows 7 Home Premium 32bit on her Zotac Mini-PC about a week back. I updated my Windows 7 Ultimate 32bit just now.

The following Important and optional updates were available.





Everything went on well and nothing untoward happened.

NoelDP said:

None of the updates are designed to affect the MBR so far as I know - and the only one that may do so is KB890830 - the MSRT, which may attempt to remove MBR malware if it finds any present. KB915597 are simply Defender updates - but are also involved in removing malware

There was an issue with the original release version of KB3004394 - which was withdrawn within 24 hours, and has since been updated and re-released. However, there was no mention of MBR problems in any of the dozens/hundreds of reports I have read.

That's why I just said one of them. As a matter of fact my MBR destroyed after the installation of the above updates as a whole. I'm glad to hear that the "KB890830" most probably did the dirty job.
In any case, thank you for your help.

NoelDP said:

If indeed the MSRT is responsible, it's ONLY because the machine was already infected with MBR malware.
You should chec it our thoroughly with a variety of virus/malware scanners.

I had already checked it with Kaspersky I.S.
Thank you