There can be several reasons responsible for interrupting your Mac’s update process:
1. Lack of free space on Mac.
2. Software malfunction.
3. Internet connection with slow speed.
4. System errors interfere with the updates.
5. Non-responsive update servers.
6. Old install data interfering with updates.
However, you can try the below DIY methods to fix the issue:
1. Ensure sufficient storage space availability.
2. Inspect your Internet connection.
3. Shut down Mac and switch it on
4. Check Apple Update Server
5. Boot your Mac in Safe Mode
6. Remove the older macOS install data
7. Rectify the Software Update preferences
Hope it helps!