Microsoft has today announced public availability of Windows 11 or the first release of Windows 11, named as Version 21H2. While the Windows 11 itself has minimum requirements for existing Windows 10 PCs to be eligible for upgrade, Microsoft has also made a list of blocking issues official.

The eligible Windows 10 PCs with these known issues will be blocked from upgrading to Windows 11. This is another thing however that initially Windows 11 will be available only for eligible “new Windows 10” PCs. Existing Windows 10 PCs will get the update on a later date until the upgrade becomes available for all eligible PCs.

Check the list of Windows 11 blocking issues provided by Microsoft below.

Compatibility issues have been found between Oracle VirtualBox and Windows 11

Status Originating update History
Confirmed N/A

Last updated: 2021-10-04, 13:28 PT
Opened: 2021-10-04, 12:18 PT
Microsoft and Oracle have found a compatibility issue between VirtualBox and Windows 11, when Hyper-V or Windows Hypervisor is installed. You might be unable to start Virtual machines (VMs) and you might receive an error.
To safeguard your upgrade experience, we have applied a compatibility hold on these devices from installing or being offered Windows 11.

Workaround: To mitigate the safeguard, you will need to remove Hyper-V or Windows Hypervisor until this issue is resolved with an update Oracle plans to release in October 2021. You can check Oracle’s progress by monitoring their ticket #20536. If you are no longer using VirtualBox, uninstalling it should also mitigate the safeguard. Please note, if there are no other safeguards that affect your device, it can take up to 48 hours before the upgrade to Windows 11 is offered.

Affected platforms:
Client: Windows 11, version 21H2
Next steps: Oracle is working on a resolution and is estimated to release a compatible version of VirtualBox in October 2021.

Note We recommend that you do not attempt to manually upgrade using the Update now button or the Media Creation Tool until this issue has been resolved. If you are trying to upgrade to Windows 11, you might encounter an upgrade compatibility hold and receive the message, “VirtualBox. Your PC requires the latest version of this app. Click Learn More for more information on how to update this app.”
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OCTOBER 2021

Compatibility issues with Intel “Killer” networking software and Windows 11

Status Originating update History
Confirmed N/A

Last updated: 2021-10-04, 13:28 PT
Opened: 2021-10-04, 12:23 PT
Compatibility issues have been found between some Intel “Killer” networking software and Windows 11. Devices with the affected software might drop User Datagram Protocol (UDP) packets under certain conditions. This creates performance and other problems for protocols based on UDP. For example, some websites might load slower than others in affected devices, with videos streaming slower in certain resolutions. VPN solutions based on UDP might also be slower.

Affected platforms:
Client: Windows 11, version 21H2
Next steps: Microsoft is working on a resolution and targeting its release in the October security update (October 12, 2021).
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OCTOBER 2021

Compatibility issues have been found between Cốc Cốc browser and Windows 11

Status Originating update History
Confirmed N/A

Last updated: 2021-10-04, 13:28 PT
Opened: 2021-10-04, 12:18 PT
Compatibility issues have been found between Cốc Cốc browser and Windows 11. Cốc Cốc browser might be unable to open and, on some devices, might cause other issues or errors.

To safeguard your upgrade experience, we have applied a compatibility hold on these devices from installing or being offered Windows 11. If your organization is using Update Compliance, the safeguard ID is 35891494.

Affected platforms:
Client: Windows 11, version 21H2
Next steps: We are presently investigating and will provide an update when more information is available.

Note We recommend that you do not attempt to manually upgrade using the Update now button or the Media Creation Tool until this issue has been resolved.