Server 2019 VM freeze, BSOD on VMware Tools 12.5.1 upgrade with Cylance agent

Products

• VMware vCenter Server 8.0

Issue/Introduction

When trying to upgrade VMware Tools 12.5.1 in a Windows Server 2019 virtual machine, the VM stops responding to input or presents a BSOD.

Other customer descriptions include:

"...having issues with 2019 servers...During the upgrade process through vCenter, tools will uninstall, but fails to reinstall/upgrade. After the machine restarts, I then attempt to do an install of VMware tools which then comes up with two error messages and then halts during the install process.  In some cases it has crashed the server causing a BSOD, and in an extreme case I've had the server fail to even restart after the BSOD."

Environment

VMware tools 12.5.1 and Windows server 2019 

Cause

The Windows Server 2019 virtual machine crashes occur due to a software conflict between the running Cylance antivirus agent version 3.2.1001.13 and the VMware Tools 12.5.1 upgrade routine.

Resolution

To resolve this issue, temporarily disable the Cylance agent during the VMware Tools upgrade, then re-enable it after installation completes:

Stop the Cylance service:

Open Services management console (services.msc)
Locate "CylanceSvc" service
Right-click and select "Stop"
Disable the Cylance service temporarily:

Right-click "CylanceSvc" service again
Select "Properties"
Change "Startup type" to "Disabled"
Click "OK"
Install VMware Tools 12.5.1:

Verify VMware Tools installation:

Confirm VMware Tools services are running
Test basic functionality (mouse integration, shared folders)
Re-enable the Cylance service:

Open Services management console (services.msc)
Right-click "CylanceSvc" service
Select "Properties"
Change "Startup type" back to "Automatic"
Click "OK"
Right-click the service and select "Start"
Verify both services are running:

Confirm Cylance agent is active and protecting the system
Confirm VMware Tools continues to function normally