- Step 1: After canceling the upgradation, wait for a few seconds or minutes.
- Step 2: To re-install the Mac OS on your system, visit the Mac App Store, or the Apple Support site.
- Step 3: Look for your Mac OS update and click the Download button.
- Step 4: Perform the on-screen instructions to complete the reinstallation.
- Step 5: If the installation is done successfully, the error 10403 code is resolved.
- Step 6: If not, check the System Status page and perform the required steps to fix the error 10403.
- Step 7: Navigate to Apple’s official page.
- Step 8: Follow the on-screen instructions. Once you reach the System Status page, look for your Mac system’s Software Update.
- Step 9: Check the icon color next to each application. If the color is green, then it means the error is caused by a third party server and not by Apple’s server.
- Step 10: Make sure that your Mac system has enough space.
- Step 11: If your Mac system does not contain enough space, then there is a chance for this issue to occur.
- Step 12: Try to update your Mac system in Safe mode. To perform it, follow the steps given below.
- Step 13: Power off your Mac system. Hold down the Shift button while turning on your Mac system.
- Step 14: You can release or free the Shift button once the Apple logo appears on your Mac system’s screen.
- Step 15: When prompted for sign in, enter your account credentials in the given field.
- Step 16: Now, try to reinstall the latest Mac update on your system.
- Step 17: If the Mac upgradation is done successfully, then the Mac update error 10403 is fixed.