That means the boot configuration file. I found [https://answers.microsoft.com/en-us/windows/forum/windows_8/windows-8-boot-issue-error-0xc000000f/2d34ca16-9ed5-40cf-88d7-08207cdf4e16?auth=1|this question was asked on the Windows Forum] and a microsoft IT replied that this guide should work: https://www.kapilarya.com/how-to-fix-error-0xc000000f-the-boot-selection-failed-because-a-required-device-is-inaccessible