When using template to deploy VMs, clicking the [Customize hardware] option will cause vCenter to hang with "out of memory" error after upgrade to vCenter 8.0.3.

Products

• VMware vCenter Server

Issue/Introduction

• When using template to deploy VM's, check the [Customize this virtual machine's hardware] option, and then click NEXT, the wizard will get stuck. After a while, vCenter UI hangs with "out of memory" error and the webpage needs to be reloaded. This happens only for particular VM templates only.
  
  
• In some scenarios, the browser hangs with error "The page isn't responding". When clicked "wait" several times, eventually browser errors out with "Page ran out of memory".

Environment

• vCenter Server 8.0.3
  
  
• vSphere ESXi 8.0.3

Resolution

If this behavior is encountered in vCenter 8.0.3, use the following verified workarounds to successfully deploy the virtual machines.

• Method 1: Post-Deployment Hardware Configuration (Recommended)

The most reliable way to bypass the UI hang is to avoid triggering the customization wizard during the initial deployment phase.

1. 1. Launch the Deploy from Template wizard.

   2. Do not check the box for "Customize this virtual machine's hardware."

   3. Complete the deployment wizard and click Finish.

   4. Once the VM is created, right-click the VM, select Edit Settings, and modify the hardware (CPU, RAM, Network) as needed before powering it on.

• Method 2: Template Refresh (Resetting Metadata)

Refreshing the template state can often clear the underlying configuration glitch causing the browser to hang.

1. 1. Locate the affected template in the vSphere inventory.

   2. Right-click the template and select Convert to Virtual Machine.

   3. (Optional) Right-click the resulting VM and select Edit Settings to ensure all hardware settings are valid.

   4. Right-click the VM again and select Template > Convert to Template.

   5. Attempt to deploy a new VM using the "Customize hardware" option to verify the fix.

• Method 3: Temporary Memory Reduction

In some instances, the crash is triggered by high memory values defined in the template's VMX file that the 8.0.3 UI fails to parse correctly.

1. 1. Convert the Template back to a Virtual Machine.

   2. Go to Edit Settings and reduce the configured Memory (e.g., if it is set to 16 GB, reduce it to 8 GB).

   3. Convert the VM back into a Template.

   4. Run the deployment wizard with the "Customize hardware" option selected.

   5. Once the wizard loads successfully, increase the memory back to the desired value within the "Customize hardware" screen.