Does the subject want to ask, "Why is the updated digital signature lost when the macbook updates the system?" The reasons are as follows: the installation package is damaged, the system time setting is incorrect, and the network problem.

1. installation package is damaged: the installation package is damaged due to an error during downloading or transmission. At this point you need to download the installation package again.

2. System time setting error: If the system time setting is incorrect, the verification will fail, resulting in problems. At this time, it is necessary to set the system time correctly.

3. Network problem: the network connection is unstable or blocked by firewall, which will lead to the failure of verification. You can try to change the network environment or turn off the firewall.