# 💿Always Eject Removable Media in VMware | Avoiding Operational Nightmares⏏️

In the world of virtualization, small oversights can lead to major headaches. One such seemingly minor detail is **forgetting to eject removable media**—virtual ISOs, USB drives, and even virtual floppy disks—from VMware virtual machines (VMs). While this may sound trivial, it can cause serious operational problems, ranging from **performance degradation and VM lockups to unexpected reboots and migration failures**.

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### **The Risks of Not Ejecting Removable Media**

#### **1\. VMotion and Storage vMotion Failures**

VMware vSphere allows for live migration of VMs using **VMotion (for compute changes)** and **Storage vMotion (for disk changes)**. However, if a VM has an **ISO mounted from a local datastore or client machine**, migration will fail with an error like:

> *"The virtual machine requires access to a device that is only available on the current host."*  
> This means that the VM is now effectively **host-locked**, preventing high availability (HA) or disaster recovery (DR) operations from working as expected.

#### **2\. VM Snapshots Becoming Bloated**

If a VM has a virtual DVD drive mounted with an ISO or an external USB drive attached, and you take a **snapshot**, the snapshot may include references to these devices. This can lead to:

* **Larger snapshot files** consuming unnecessary storage.
    
* **Restoration issues** if the ISO or USB is missing when rolling back.
    
* **Performance degradation** when running from a snapshot state.
    

#### **3\. Unexpected VM Boot Failures**

Some VMs are configured to boot from CD/DVD or removable media as their first boot device. If an outdated or invalid ISO is still mounted, the VM may:

* Fail to boot.
    
* Get stuck in a **boot loop**.
    
* Attempt to load an unintended OS or recovery environment.
    

This is particularly dangerous in production environments where a reboot could happen unexpectedly due to patching or power failure.

#### **4\. USB Devices Causing Resource Contention**

When a USB device is connected to a VM using **USB passthrough**, it is effectively removed from the ESXi host and dedicated to that VM. If the USB is not ejected:

* Other VMs cannot access the device.
    
* The host may experience **resource contention** if multiple VMs try to claim it.
    
* If the VM is restarted, the device may **fail to reconnect properly**, requiring manual intervention.
    

#### **5\. Stale ISO References Blocking VM Operations**

If a VM has a CD/DVD drive mapped to an ISO stored on a **disconnected datastore**, certain operations—like power on, reconfiguration, or migration—may fail with errors such as:

> *"Device 'CD/DVD drive 1' is backing a datastore that no longer exists."*  
> This leads to **administrative overhead**, requiring manual removal of the stale device before operations can proceed.

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### **Best Practices for Handling Removable Media in VMware**

1. **Always Eject ISOs After Installation or Maintenance**
    
    * In vSphere, navigate to the VM settings and set the CD/DVD drive to **“Client Device”** or **“Host Device”** instead of a specific ISO.
        
    * Use the vSphere Web Client or PowerCLI to ensure no unnecessary ISOs are attached.
        
2. **Remove USB Devices When No Longer Needed**
    
    * Detach USB devices properly via the VMware Remote Console or vSphere Client.
        
    * Avoid using USB passthrough unless absolutely necessary—prefer network-based solutions (e.g., file shares).
        
3. **Automate Checks with PowerCLI**  
    Run a periodic script to check for mounted ISOs across all VMs:
    
    ```plaintext
    Get-VM | Get-CDDrive | Where-Object { $_.IsoPath -ne $null } | Select VMName, IsoPath
    ```
    
    This helps ensure no VM is unknowingly holding onto an ISO.
    
4. **Verify Boot Order in BIOS Settings**
    
    * Set **hard disk as the first boot option** to prevent accidental boots from outdated media.
        
    * Disable unnecessary bootable devices if they are not required.
        
5. **Audit and Remove Stale Device References**
    
    * Regularly review VMs for **orphaned devices** that might be mapped to non-existent datastores.
        
    * Use **vCenter alarms** to detect and alert when an ISO is mounted for an extended period.
        

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### **Wrap**

Forgetting to eject removable media in VMware might not seem like a big deal—until it **breaks your VM migration, slows down performance, or prevents booting when you need it most**. By following best practices and automating checks, you can **avoid unnecessary outages and reduce troubleshooting time**.

So next time you finish installing software or transferring files on a VM, **do yourself a favour—eject that ISO!** 🚀