Configure the cloud block timeout period
When Windows Defender Antivirus finds a suspicious file, it can prevent the file from running while it queries the Windows Defender Antivirus cloud service.
The default period that the file will be blocked is 10 seconds. You can specify an additional period of time to wait before the file is allowed to run. This can help ensure there is enough time to receive a proper determination from the Windows Defender Antivirus cloud service.
Prerequisites to use the extended cloud block timeout
Block at first sight and its prerequisites must be enabled before you can specify an extended timeout period.
Specify the extended timeout period
You can use Group Policy to specify an extended timeout for cloud checks.
On your Group Policy management computer, open the Group Policy Management Console, right-click the Group Policy Object you want to configure and click Edit.
In the Group Policy Management Editor go to Computer configuration and click Administrative templates.
Expand the tree to Windows components > Windows Defender Antivirus > MpEngine
Double-click Configure extended cloud check and ensure the option is enabled. Specify the additional amount of time to prevent the file from running while waiting for a cloud determination. You can specify the additional time, in seconds, from 1 second to 50 seconds. This time will be added to the default 10 seconds.