Under what condition can the attorney-client privilege be waived?

The attorney-client privilege can be waived when the client agrees to it. This privilege is designed to encourage open and honest communication between the client and the attorney, protecting the confidentiality of those discussions. Thus, the client has the authority to decide whether to maintain or waive the privilege.

The concept hinges on the client’s control over their own information; they can choose to disclose certain details if they feel it serves their interests. Waiver can also occur through actions that imply the client no longer wishes to maintain such confidentiality, but fundamentally, it is the client's decision to make.

The other conditions mentioned do not accurately reflect how the privilege operates; an attorney's approval alone does not suffice for a waiver, and the privilege does not automatically end when a case closes or when there is a lawsuit against the attorney. The key element remains that the client's consent is necessary for any waiver of privilege to take effect.