Knowledge

ERROR_SETCOUNT_ON_BAD_LB - 1433 (0x599)

LB_SETCOUNT sent to non-lazy list box.

Updated: Feb 21, 2026

Technical Background

The error code ERROR_SETCOUNT_ON_BAD_LB with the numeric value 1433 and hexadecimal representation 0x599 is encountered when an attempt is made to set the count of items in a non-lazy list box control using the LB_SETCOUNT message. This error indicates that the operation was performed on an object that does not support or recognize this specific API.

Error Details

The LB_SETCOUNT message is intended for use with lazy list boxes, which are designed to dynamically adjust their item count based on user interaction or other conditions. Attempting to set the count of items in a non-lazy list box using this message will result in an error being generated.

Common Causes

  • Invalid Parameter Values: The LB_SETCOUNT message was sent to a control that is not a lazy list box, leading to the generation of this error code.
  • Incorrect Object Type: The operation context did not involve a lazy list box, but rather another type of list box or control.

Real-World Context

In Windows applications, list boxes are commonly used for displaying and managing lists of items. Lazy list boxes are optimized to reduce memory usage by dynamically adjusting the number of displayed items based on user interaction. Non-lazy list boxes maintain a fixed set of items at all times, making them less suitable for scenarios where dynamic item counts are required.

Is This Error Critical?

The criticality of this error depends on the specific application and its requirements. If the application relies heavily on lazy list box functionality, encountering this error could indicate a significant issue that needs to be addressed. However, in contexts where non-lazy list boxes are used, this error may not have severe consequences.

How to Diagnose

To diagnose the cause of ERROR_SETCOUNT_ON_BAD_LB, follow these steps:

  1. Review Operation Context: Ensure that the operation was intended for a lazy list box control and not another type of list box or control.
  2. Validate Parameters: Verify that the message being sent is correctly identified as LB_SETCOUNT and that it is directed to the appropriate control.
  3. Confirm Object Types: Use debugging tools or code inspection to confirm that the object in question is indeed a lazy list box and not another type of control.
  4. Verify Input Data: Check if there are any data inconsistencies or incorrect values being passed as parameters to the LB_SETCOUNT message.

How to Resolve

To resolve this issue, consider the following steps:

  1. Correct Parameter Usage: Ensure that the correct list box control is targeted and that the appropriate API messages are used for its operations.
  2. Adjust Operation Context: If necessary, adjust the application logic to ensure that lazy list boxes are only manipulated using their intended APIs.
  3. Restore Data: In cases where data corruption or incorrect values may have contributed to this error, restore the correct state of the control and reinitialize it if needed.
  4. Retry Operation with Valid Inputs: Attempt to perform the operation again with valid inputs to ensure that the issue is resolved.

Developer Notes

Developers should be aware that using LB_SETCOUNT on non-lazy list boxes will result in this error code being generated. It is important to validate control types and use appropriate APIs for each type of list box to avoid such errors.

Related Errors

  • ERROR_INVALID_PARAMETER: This error may occur if the parameters passed to the LB_SETCOUNT message are invalid or incorrect.
  • ERROR_NOT_SUPPORTED: If the operation is not supported by the control, this error might be generated instead of ERROR_SETCOUNT_ON_BAD_LB.

FAQ

Q: What does the ERROR_SETCOUNT_ON_BAD_LB error mean?

A: This error indicates that an attempt was made to set the count of items in a non-lazy list box using the LB_SETCOUNT message, which is not supported by such controls.

Q: How can I prevent this error from occurring?

A: Ensure that you are targeting lazy list boxes with the appropriate API messages and validate control types before performing operations on them.

Summary

The ERROR_SETCOUNT_ON_BAD_LB error code 1433 is generated when an attempt is made to set the count of items in a non-lazy list box using the LB_SETCOUNT message. This error highlights the importance of proper parameter validation and understanding control types in Windows applications.