Alternate operating systems must not be permitted on the same system.

Severity
Group ID
Group Title
Version
Rule ID
Date
STIG Version
mediumV-220709SRG-OS-000480-GPOS-00227WN10-00-000055SV-220709r991589_rule2025-02-253
Description
Allowing other operating systems to run on a secure system may allow security to be circumvented.
ℹ️ Check
Verify the system does not include other operating system installations. Run "Advanced System Settings". Select the "Advanced" tab. Click the "Settings" button in the "Startup and Recovery" section. If the drop-down list box "Default operating system:" shows any operating system other than Windows 10, this is a finding.
✔️ Fix
Ensure Windows 10 is the only operating system on a device. Remove alternate operating systems.