Forum Discussion

Brass Contributor

Aug 29, 2025

Solved

MS Defender - Installation Error version 101.25072 on macOS

Dear experts, The latest version of MS Defender can't be installed. I'm getting an error message since release date (5th Aug). I have tested to restart the computer, tested with different networks, ...

BrandonJ365
Sep 08, 2025
FYI...MS has this posted on their service health status page. They have a fix in the works but sounds like it will be a "side channel" upgrade of some kind. I'm betting we'll be having to push a shell script via MDM that will end up doing a "rip and replace" of sorts.
https://admin.cloud.microsoft/?#/servicehealth/:/alerts/DZ1144032

apr

Copper Contributor

Sep 04, 2025

Same for me, this is the installation error from the logs:

[2025-09-02 07:36:56.105370 +0000][StopUI]: [I]: Stopping UI
[2025-09-02 07:36:56.183523 +0000][StopUI]: [I]: Stop: killall: warning: kill -kill 1274: Operation not permitted

.... "code":"UIStopRejected", "text":"Cannot stop Defender UI process, tamper protection in state "block""

Followings are NOT worked for me:

Setting the tamper mode to "audit" (mdatp config tamper-protection enforcement-level --value audit)

Killing all defender process (not trivial) before installation

This worked:

offboarded the device (script method)

downloaded an onboard installation package: installed without problem

onboarded the device (script method)

(maybe offboard/onboard is not necessery, just running the latest installation package is enough)