Hello IbrahimJaved-3732,
Thank you for posting here.
Please on one problematic machine, check if the group policy setting was applied successfully.
Logon this machine using Administrator account.
Open CMD (run as Administrator).
Run gpupdate /force and click Enter.
Run gpresult /h C:\gpo.html and click Enter.
Open the gpo.html and check if the gpo setting "Removable Storage->Access All Removable Storage classes: Deny all access==>Enabled" is under the "Computer Details".
Meanwhile, please check the corresponding registry value is 1.
Registry Hive HKEY_LOCAL_MACHINE
Registry Path Software\Policies\Microsoft\Windows\RemovableStorageDevices
Value Name Deny_All
Value Type REG_DWORD
Enabled Value 1
Hope the information above is helpful.
If you have any question or concern, please feel free to let us know.
Best Regards,
Daisy Zhou
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