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In this case, administrators can deploy registry key settings and prevent .NET Framework 4.8.1 from being provided to these devices. For more information on how to use this blocker registry key, see the following Microsoft Knowledge Base article: How to temporarily block the installation of .NET Framework 4.8.1 - Microsoft Support
Please note: Please follow the steps in the link carefully. If the registry is modified incorrectly, serious problems can occur. Before modifying the registry, back up the registry to restore it if a problem occurs.
I hope the information above is helpful.
Best Regards,
Yanhong Liu
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