Root Cause Analysis:

Steps Taken:

1. Ping Test from Another VM on Same Host:

   • VM is unreachable.

2. Console Access via vSphere Client:

   • The VM’s screen is frozen; OS is not responsive

   • Mouse or keyboard input doesn’t register.

3. Check Host Resource Usage:

   • ESXi host is running normally, no CPU or memory pressure.

   • Other VMs are working fine.

4. Check VM Logs (vmware.log):

   • Found repeated entries:vcpu-0| … VMX has encountered an unrecoverable error…

5. Check Host Hardware and Storage:

   • No storage disconnects or hardware alerts

   • VM files are intact on the datastore.

Solution:

Short-term Fix:

• Performed a hard reset of the VM from the vSphere Client (“Power Off” > “Power On”)

• VM booted successfully; services restored.

Permanent Fix:

• Investigated the crash logs in Windows Event Viewer after reboot: found faulty Windows Update that caused a kernel-level crash

• Uninstalled the update and paused automatic updates

• Created a scheduled snapshot and backup routine to ensure recoverability

• Added vSphere alarms for future VM unresponsiveness based on CPU and network inactivity.