Sometimes, you need to exclude the folder or specific file extension from being scanned by Windows Defender.
Below is the PowerShell command that you can use to do that :

1. Open Windows PowerShell with elevated permissions.
2. To exclude the specific folder (e.g C:\Folder1). Run the following command Add-MpPreference -ExclusionPath “C:\Folder1”
3. Another case, if you want to exclude the .txt file type/extension. Run the following command Add-MpPreference -ExclusionExtension “txt”

For more detail about this command, you can check here.