Some newer versions of Mac will ask for your password during setup, and setup will complete before the dialog to allow the system extensions/certificate changes shows.

Click Ok to allow the Avast Business Antivirus installer to access your downloads folder.

Click Close when the installation is complete, then click Move to Trash.

Optionally, uncheck the box if you do not want Google Chrome installed as your default browser, then click Continue.

When prompted, click Quit Now, then close the Security & Privacy window

Select Privacy and enable Full Disk Access for Avast Business Antivirus.

Try the following solutions: Download your Avast setup file on a different PC (using the relevant link from this article), then transfer the file to your original PC using a USB or portable hard drive.

Click the lock icon, enter your Administrator Password and click Unlock, then click Allow If you don't see the Digital Signatures tab in the Properties menu, your setup file is incomplete or corrupted.

When the System Extension Blocked notification appears, click Open Security Preferences, then do the following:.

Click Ok to allow Avast Business Antivirus to access your downloads folder.

If prompted, use your Touch ID or Administrator Password to grant permission for the installation, then click Install Software.

If you would like to make changes to the default setup, click Customize.

Click Continue to confirm you have read the End User License Agreement and click Agree to confirm you accept the terms.

Avast Antivirus protects your computer from viruses, spyware, ransomware, and other kinds of malware programs and Internet threats.

Click Continue in the pop-up, review the Privacy Policy, then click Continue Avast Free Antivirus provides protection to your computer from viruses, spyware, ransomware, phishing attack, and other malware.

Double-click the Avast Business Antivirus icon, then close the window.

Copy the installation file (.dmg) to a location accessible by your device, and ensure no other application or antivirus software is running.

When the installer is downloaded, you can run it on the device you would like to install Antivirus on. For Avast Business Antivirus, click on the Business tab and select either the Online or Offline installer for the Antivirus version you have. For unmanaged Avast Business Antivirus and Small Office Protection, you can download the Avast Business Antivirus installer from and the Small Office Protection installer from here.

Avast antivirus installer running