In what cases is locking established during testing?

In testing, a blocker is set when a discovered defect makes it impossible or critically difficult to continue testing the main functionality or the entire module/system as a whole.

Examples of cases when a blocker is set:

• Inability to authorize/register: The user cannot log in or create an account, which blocks access to most functions.
• Critical failure during application startup: The application crashes or does not start at all.
• Inaccessibility of key functionality: The main function of the product (e.g., placing an order in an online store, sending an email in an email client) does not work at all.
• Massive data corruption or loss: The defect leads to loss or incorrect modification of a large volume of user data.
• Security breach: A vulnerability is found that allows unauthorized critical access or malicious actions.
• Inability to continue the test scenario: The defect interrupts the execution of a critically important test scenario at an early stage.
• UI/UX making the application unusable: For example, a completely blank screen, elements overlapping each other so that interaction is impossible.