Unusual high corruption of OST files

[Remko]

Hi, We are receiving an unusual high amount of failing "Kasperksy for Workstation 11.0.0.6499" Outlook add-in's and corrupt OST files since we have migrated our machines from Windows 7 to Windows 10 and Office Version from 2010 to 2016. We have an on premise Exchange 2013 server and the Kasperksy for Workstation version has remained unchanged. So only the Office version and the OS has changed on the workstations. So far I have not been able to find the culprit. I was wondering if more people experience a failing Kasperksy add-in or if they see higher than usual corruption of the OST files. As the Kasperksy add-in is the only add-in we have in Outlook, my first thought was that perhaps Kasperksy could be a culprit to this. We had negative experiences with this add-in in the past causing very slow Outlook performance. Outlook disabled the following add-in(s): ProgID: OutlookKLAvPlg.Addin_25135DE3-BB52-4185-9E7D-A72F82E5A224 GUID: {01D7D203-BF4B-4E4E-8DE9-169082FA6386} Name: Kaspersky Outlook Anti-Virus Addin Description: Addin for anti-virus protection Load Behavior: 0 HKLM: 1 Location: c:\program files (x86)\kaspersky lab\kaspersky endpoint security for windows\mcou.dll Threshold Time (Milliseconds): 500 Time Taken (Milliseconds): 531 Disable Reason: This add-in caused Outlook to close slowly. Policy Exception (Allow List): 0

[Konstantin Antonov]

Hi, Could you please provide full GSI report from the affected host. Thank you!

[Remko]

As requested: Download link No upload option available?

[Remko]

I have noticed that the files have not been downloaded yet. Please be advised that the files will be available till May 15th. Remko

[Nikolay Arinchev]

Hi, Thank you for that info! Is it possible to update KES to 11.1 version?

[Remko]

Is it possible to update KES to 11.1 version?

I suppose this is possible but will take some time to implement (Management of Change) Are you suspecting Kasperksy as a possible culprit?

[Nikolay Arinchev]

You can also test it by trying to reproduce the problem without KES during update process. Please make it for one testing PC.

[Remko]

My estimate is that in approx 5% of the newly deployed machines the problem has occured so far. Some people complain that Outlook stops fetching mail. When we rebuild the OST every thing is back to normal. Others complain that an Outlook add-in crashes. When we investigate, it is Kasperksy as shown above. The biggest problem I have is that I cannot reproduce this. Keep also in mind that it is a software refresh, not a hardware refresh and the OS is not upgraded but newly imaged.