ADMX Viewer
Microsoft.Policies.WindowsDefender• Machine

Configure the 'Block at First Sight' feature

This feature ensures the device checks in real time with the Microsoft Active Protection Service (MAPS) before allowing certain content to be run or accessed. If this feature is disabled, the check will not occur, which will lower the protection state of the device. Enabled – The Block at First Sight setting is turned on. Disabled – The Block at First Sight setting is turned off. This feature requires these Group Policy settings to be set as follows: MAPS -> The “Join Microsoft MAPS” must be enabled or the “Block at First Sight” feature will not function. MAPS -> The “Send file samples when further analysis is required” should be set to 1 (Send safe samples) or 3 (Send all samples). Setting to 0 (Always Prompt) will lower the protection state of the device. Setting to 2 (Never send) means the “Block at First Sight” feature will not function. Real-time Protection -> The “Scan all downloaded files and attachments” policy must be enabled or the “Block at First Sight” feature will not function. Real-time Protection -> Do not enable the “Turn off real-time protection” policy or the “Block at First Sight” feature will not function.

Policy Details

Policy Name
DisableBlockAtFirstSeen
Registry Key
Software\Policies\Microsoft\Windows Defender\Spynet
Value Name
DisableBlockAtFirstSeen
Supported On
At least Windows Server 2016, Windows 10
OMA-URI (CSP)
ADMX_MicrosoftDefenderAntivirus/DisableBlockAtFirstSeen
OS Build Version:10.0.22000, 10.0.19043.1202, 10.0.19042.1202, 10.0.19041.1202
CSP Version:10.0
Conflict Resolution:LastWrite
Allowed Editions:
EnterpriseEnterprise NProfessionalProfessional NEnterprise EvaluationEnterprise N EvaluationEducationEducation NEnterprise SEnterprise S NEnterprise S EvaluationEnterprise S N EvaluationHolographic BusinessPro Single LanguagePro ChinaPro WorkstationPro Workstation NPro For EducationPro For Education NEnterprisegEnterprisegnServerrdshIotenterpriseIotenterprisesCloudeditionnCloudeditionIotenterpriseskIotenterpriseseval
Policy State Values
Enabled: 0
Disabled: 1
Available Languages
en-us