easyMultiple Choice
220-1201 Practice Question: A technician is troubleshooting a VM that fails…
A technician is troubleshooting a VM that fails to boot with an error 'Operating system not found'. The VM was just created from an ISO file. What is the most likely cause?
⚠ Common exam trap
220-1201 often tests whether candidates jump to hardware failure causes (corrupted ISO, missing disk) when the simplest explanation is a boot order misconfiguration, so the trap is overlooking the empty-disk-first scenario.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The VM's boot order is set to hard disk first, and the hard disk is empty
The most likely cause is that the VM's boot order is set to hard disk first, and the hard disk is empty because the OS has not yet been installed from the ISO. When a VM is newly created from an ISO, the ISO must be mounted and the boot order must prioritize the CD/DVD drive so the installer can run; otherwise the firmware looks at the empty virtual disk and reports 'Operating system not found.'
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The ISO file is corrupted
Why it's wrong here
A corrupted ISO file would typically lead to errors during the loading of the operating system installer or boot environment itself, such as 'checksum mismatch' or 'read error' messages. The VM would attempt to access the ISO, but fail to properly execute the boot instructions contained within it, rather than reporting that no operating system was found on any device. This type of error indicates a problem with the *content* of the boot medium, not its absence or the inability to locate it.
- ✓
The VM's boot order is set to hard disk first, and the hard disk is empty
Why this is correct
When the VM's boot order prioritizes the virtual hard disk and that disk is empty or unformatted, the virtual BIOS/UEFI firmware will attempt to locate a bootable operating system on it. Failing to find a valid boot sector or EFI partition, the VM will then display an 'Operating system not found' error. This occurs because the system cannot proceed to the next boot device in the sequence until the primary, empty hard disk has been exhausted as a boot option, even if a bootable ISO is attached but lower in the boot order.
- ✗
The VM has insufficient RAM
Why it's wrong here
Insufficient RAM would primarily manifest as a failure for the operating system to fully load or operate stably once it begins to boot, often resulting in a system crash, freeze, or extremely slow performance. The VM's firmware would still successfully identify and attempt to boot from a valid storage device containing an OS. The 'Operating system not found' error specifically indicates an inability to locate *any* bootable OS on the configured devices, not a resource limitation during OS execution.
- ✗
The virtual hard disk is not attached
Why it's wrong here
If the virtual hard disk is not attached to the VM, the virtual BIOS/UEFI would simply skip that device during the boot sequence. The VM would then proceed to attempt booting from the next device in the configured boot order, such as a virtual CD/DVD drive with an attached ISO. An 'Operating system not found' error would only occur if *no* bootable device, including any attached ISOs, was found throughout the entire boot sequence after exhausting all options in the boot order.
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Same concept, more angles
1 more way this is tested on 220-1201
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A technician is troubleshooting a VM that fails to boot with the error 'Operating system not found.' The VM was created from a template that uses a virtual SCSI controller. The technician verifies that the ISO file is attached to the virtual DVD drive and the boot order is set to DVD first. What is the most likely cause of the error?
medium- A.The virtual SCSI controller is not compatible with the guest OS.
- B.The ISO file is corrupted or incomplete.
- ✓ C.The virtual DVD drive is not connected to the VM’s IDE controller.
- D.The VM’s BIOS is set to UEFI instead of legacy BIOS.
Why C: The 'Operating system not found' error occurs when the VM cannot boot from the configured boot device and falls through to the virtual SCSI disk, which has no OS. Although the ISO is attached to the virtual DVD drive, the drive itself may not be connected to the VM's controller, so the VM cannot read the ISO during boot. The VM was created from a template that uses a virtual SCSI controller, which often means no IDE controller is present for the DVD drive. A UEFI/legacy mismatch can cause boot issues, but the specific error and the SCSI-template clue make the disconnected DVD drive the most likely cause.
JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official CompTIA exam blueprint
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