Opening installers on old MacOS
Creation date: 9/22/2026 2:17 PM
Updated: 9/22/2026 2:17 PM
If you get a "mac cannot check for malicious software" error when trying to open a downloaded application to install it, try this:
Click OK on the warning dialog box.
- Click the Apple menu in the top-left corner of your screen.
- Select System Settings.
- Click Privacy & Security in the sidebar.
- Scroll down to the Security section on the right. You should see a message stating that the app was blocked.
- Click Open Anyway next to the blocked app's notice. (Note: This button is only available for one hour after you try to open the app).
- Enter your login password to confirm the exception.
- Click Open on the final warning prompt.