If you are trying to update to or install Windows 10, version 2004 or Windows 10, version 20H2, you might encounter an update compatibility hold and receive the message, "Your PC has hardware that isn't ready for this version of Windows 10. Windows Update will automatically offer you this version of Windows 10 once the issue has been resolved."
An incompatibility issue has been found with Windows 10, version 2004 or Windows 10, version 20H2 when using an Thunderbolt NVMe Solid State Disk (SSD). On affected devices, when plugging in a Thunderbolt NVMe SSD you might receive a stop error with a blue screen and "DRIVER_VERIFIER_DMA_VIOLATION (e6) An illegal DMA operation was attempted by a driver being verified." Affected Windows 10 devices will have at least one Thunderbolt port and any currently available version of the driver file stornvme.sys.
To safeguard your update experience, we have applied a compatibility hold on Windows 10 devices with affected drivers from being offered Windows 10, version 2004 or Windows 10, version 20H2. If your organization is using Update Compliance, the safeguard IDs is 29991611.
This issue was resolved in KB4586853 and the safeguard hold has been removed as of December 11, 2020. Please note, if there are no other safeguards that affect your device, it can take up to 48 hours before the update to Windows 10, version 2004 or Windows 10, version 20H2 is offered.