MCXTools.log - what is it and why is it so large?

[Utilizator]

We have a user who has discovered a log file on their MacBook called MCXTools.log that is being endlessly written to with the same entry (ID's have been obfuscated for security):

Aug 27 13:45:39 mdmclient[20216] [0:MDMDaemon] Using MDM profile: <DeviceEnrollment> [CloudConfiguration:SetupAssistant] EnrollID: XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX (User:XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX) <Payload: JAMF Manual Enrollment Payload: MDM (<com.apple.mdm> 00000000-0000-0000-A000-XXXXXXXXXXXX:00000000-0000-0000-A000-XXXXXXXXXXXX) from profile: MDM Profile (00000000-0000-0000-A000-XXXXXXXXXXXX:00000000-0000-0000-A000-XXXXXXXXXXXX)>

It has been writing these lines (and others) endlessly ever since it was enrolled. I cannot find any information on the internet about this log file and wondered if anyone has seen this before and what it is doing?

[AJPinto · Accepted solution]

MCX is more or less a precursor to MDM, it's how macOS handled managed preferences back in the day. MacOS still uses MCX to handle some MDM functions. How large is the log file? I'd expect it to have a ton of text, but I think macOS trims off at 100mb for most of the logs unless something is wrong.

[Utilizator]

Thanks for the info AJPinto (I knew you'd reply hehe)

The log is only 7.9MB, just curious as to what it is... turns out all our Managed Macs have this file, I didn't spot this initially as I am non-admin (as are 99% of our estate) but this user is an admin so this log appeared in his Console.app

[AJPinto]

When I see something interesting, I will be summoned lol. Cheers!!!