Issue/Introduction
The normal VMTools installation flow mounts an ISO to a virtual CD-ROM drive. If the user deletes the entire drive after installing the OS instead of only unmounting the ISO, the page finds that vmCdRoms is empty and prevents installation.
Symptoms
- The page displays "The virtual machine does not have a CD-ROM drive. Add a CD-ROM drive and try again." or equivalent text.
- There is no CD-ROM device in the VM details.
- Key differentiator: there is no CD-ROM device, rather than a CD-ROM device with no ISO mounted.
Environment
Verified on ZSphere 4.10.26 and 5.1.0. Both Windows and Linux normal ISO installation paths can encounter this issue.
Possible causes
First confirm the number of CD-ROM devices on the page or through read-only API inventory. Follow this article only when the device list is empty. If a drive exists but the error remains, check consistency among the page cache, API inventory, and VM XML.
Issue classification
- Type: Operation issue/product guardrail scenario.
- Known issue: Yes. ZSV-12079 is Closed/Won't Do; the page prompt was verified on 5.1.0. ZSV-12082 is Closed/Duplicate and its comments confirm the issue on 4.10.26.
- Root cause: The user deleted the entire virtual CD-ROM drive, leaving no mount target for the VMTools ISO.
- Confidence: High, provided that inventory confirms an empty CD-ROM list.
Resolution
Check 1: Confirm hardware devices on the page
- Read-only path: VM Details > Configuration/VM Hardware > CD-ROM Drive.
- If there is no CD-ROM drive: This article applies.
- If an empty drive or a drive with an ISO exists: Do not classify it as a missing drive. Collect page and API evidence and escalate.
Check 2: Confirm recent operations
- Read-only path: virtual machine audit/operation logs. Search for deleting a CD-ROM drive, unmounting an ISO, and installing VMTools.
- If the record shows deletion of the CD-ROM device: The root-cause chain is complete.
- If it shows only an ISO unmount: The device should still exist. Check inventory.
Check 3: Confirm the VM state and change conditions
- Read-only checks: VM state, current tasks, and whether an online CD-ROM drive can be added.
- If the running state does not support adding the drive: An approved shutdown window is required.
- If a snapshot, backup, or other task is in progress: Wait for it to finish; do not modify hardware concurrently.
Recommended actions
The operations in this section must be performed manually by an administrator with the required permissions.
During a maintenance window, the customer adds an empty CD-ROM drive in the VM hardware configuration, saves the change, and runs VMTools installation again. If the running state does not support adding it, shut down the VM under business approval, add the drive, and restart the VM. Record the original hardware inventory before the change. If the addition fails, remove the new device and submit the logs. Do not combine "unmount ISO" and "delete CD-ROM drive" into one step.
Long-term solution
Retain the missing-drive prompt and operation guardrail. Documentation should state that after OS installation, users must only unmount the ISO and must not delete the CD-ROM device.
Additional information
When to escalate
- The page shows an existing CD-ROM drive but still reports it as missing.
- Adding the drive fails, or downtime is required but no maintenance window is available.
- VMTools installation still fails after the ISO is mounted successfully.
Information to collect
ZSphere/guest OS versions, VM hardware page, CD-ROM inventory, operation audit, VM state, screenshot of the installation error, and VM UUID (redact it when submitting).