It is honestly disturbing to see CCleaner actively prevent users from disabling it at startup.
The application does not appear in the operating system’s startup apps, and even worse, it is also hidden from CCleaner’s own startup management and checkup tools. This is not a technical limitation, it is a deliberate design choice.
A utility that claims to give users control over their system should not be obscuring its own behavior. Blocking visibility and control over startup processes directly contradicts the purpose of a system optimization tool. At that point, it stops being helpful and starts behaving like the very software it claims to clean.
Transparency and user control are basic expectations. If an application needs to hide itself to ensure it keeps running, that alone should raise serious questions about trust and intent.