Step 1. Go to your applications folder.
Step 2. Find the installer for macOS
Step 3. Right click on the installer and click "Show Package Contents".
Step 4. Click on folder named "Contents".
Step 5. Click on the folder named "SharedSupport".
Step 6. Delete the file named "InstallInfo.plist".
Step 7. Enter your administer password to confirm.
Step 8. Now open the installer.