Microsoft blocks Windows 11 upgrades if customers use applications that create registry keys using certain non-ASCII characters.
As the company explains, on affected systems, these apps might not be able to open and could also cause other issues or errors in Windows 11, version 21H2, including blue screens.
“Compatibility issues have been found between applications using non-ASCII characters in their registry keys or subkeys and Windows 11,” Microsoft explains.
“Affected applications may not be able to open and cause other problems or errors in Windows, including the possibility of receiving an error with a blue screen.”
To make matters worse, in some cases registry keys with non-ASCII characters can also be beyond repair.
While it doesn’t say so in the Windows Health Dashboard entry for the known issue, Microsoft has merged it with a previous bug preventing Cốc Cốc browser users from upgrading to Windows 11.
“If your organization uses update compliance, the protection ID for devices with the Cốc Cốc browser is 35891494,” says Redmond.
Microsoft has applied a compatibility suspension to protect the user experience by preventing affected Windows devices from being offered or installing Windows 11.
Customers are also advised not to attempt to upgrade manually through the Update now or to use the Media Creation Tool until a fix is available.
Eight known Windows 11 issues currently under investigation
Besides this, Microsoft is also investigating seven other known issues that are caused by hardware or software incompatibilities that can lead to system instability or crashes.
The full list of Windows 11 known issues discovered so far includes:
To protect against potential upgrade issues, Microsoft has placed backups for some of the above issues to prevent users from upgrading to Windows 11.
Microsoft is investigating the issues and updates to address them will be released with October Patch Tuesday for some of them.
Windows 11 was released worldwide last week and is now rolling it out through Windows Update to new Windows 10 devices and those preloaded with Windows 11.
All Windows 10 users can upgrade to Windows 11 using Windows Update if their systems came with compatible hardware. Devices must also be running Windows 10 2004 and later AND have installed at least the latest updates for September 2021.
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