Increasing file cmk_mail.log on all monitored Windows systems

[UT2019]

CMK version: 2.0.0p18 (CEE)
OS version: Windows Server 2012 R2, Windows Server 2016

Error: We have a file C:\Users\Public\cmk_mail.log on all monitored Windows systems which is constantly getting bigger. On some systems it is already >1GB. It contains very much logging, which seems to be always the same:

2021-03-31 13:31:26.912 Mail slot "\\.\mailslot\Global\WinAgent_0" was opened
2021-03-31 13:32:27.306 Mail slot "\\.\mailslot\Global\WinAgent_0" was opened
2021-03-31 13:32:27.370 Mail slot "\\.\mailslot\Global\WinAgent_0" was opened
2021-03-31 13:32:27.526 Mail slot "\\.\mailslot\Global\WinAgent_0" was opened
2021-03-31 13:32:27.553 Mail slot "\\.\mailslot\Global\WinAgent_0" was opened

The file is accessed by check_mk_agent.exe, so I guess it is created and used by checkmk.

Does anybody know what this file is for and why it is getting so big?

Best regards,
UT2019

[andreas-doehler (Andreas)]

That is a question for @SergejKipnis

[UT2019]

Nobody an idea what this is about?

[Check_MKUser]

Did you find a solution for this problem? I am struggeling with exactly the same situation right now and i don’t know how to fix it. Thanks in advance

[UT2019]

No, I did not find a solution and sadly actually nobody replied, so I delete those files manually when they get too big.

[SergejKipnis (Sergej)]

Sorry for such long delay, I’m on it.

The situation is quite strange because this is quite old regression, presumably fixed in werk 12330.

P.S. Do not hesitate to ping me again

[SergejKipnis (Sergej)]

Such behavior is a regression in 2.0
The werk 123300 must eliminate the Problem.
If the problem still exists, then you have to update the Agent

[katamadone]

Can commit that the werk Disable Windows agent mail API tracing seems to solve that.
We’ve installed the server Checkmk Enterprise Edition 2.1.0p17 and the agent 2.1.0p16 on the server and the stopped increasing since 23.11.2022 (when we installed 2.1.0p16 agent).