Will software signed with an expired code signing certificate still run normally?

The "validity period" of a code signing certificate mainly affects the trust status of newly signed files. Its impact on the operation of already signed files falls into two scenarios:

• Timestamp not enabled: If no timestamp was added during signing, the system will consider the signature invalid after the certificate expires.
• Timestamp enabled: If the timestamp option was selected during signing, the system will verify "whether the certificate was within its validity period at the time of signing" — even if the certificate later expires, as long as the timestamp remains valid, the signed file will still be trusted.