Recently, Apple has released a new security mechanism system in macOS 10.13 (High Sierra) which will automatically prevent its users from installing programs that aren’t downloaded from the App Store unless the user manually allows this from “System Preferences”. Once the user has allowed the installation manually, all other software developed by that developer will be allowed through automatically without requiring users’ approval again.
Fail to install virtual sound card in macOS 10.13 (High Sierra)?
Some macOS 10.13 users who installed Apowersoft Mac Screen Recorder software may see the error message “Virtual sound card can’t be detected, install it now?” pops up but fail to install “Apowersoft_AudioDevice” virtual sound card by clicking “Yes” in the dialogue. Reinstallation and reboot won’t help in this situation because it has already been blocked the system and if you do nothing at this stage then Apowersoft program will not work correctly and fail to capture computer system sound.
To fix this issue and enable the virtual sound card for installing, please refer to the step-by-step instruction below.
Step one: Click on the “System Preferences” icon in the Dock or navigate to Apple menu and go to “System Preferences”.

Step two: Click “Security & Privacy” and then you will see the alert message “System software from developer “Apowersoft Limited” was blocked from loading” in this window.
Step three: In there, click on the “Allow” button displayed next to the alert message.

Note: If you can’t click on “Allow” button, you need to unlock the pane. Simply click on lock icon located at the bottom of the pane, then enter your admin password.
Step four: After that, you can reboot your computer first and then reinstall our screen recorder.
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