ERROR_DEBUG_ATTACH_FAILED - 590 (0x24E)
{Unexpected Failure in DebugActiveProcess} An unexpected failure occurred while processing a DebugActiveProcess API request. You may choose OK to terminate the process, or Cancel to ignore the error.
Updated: Feb 21, 2026
Technical Meaning
The error code ERROR_DEBUG_ATTACH_FAILED (590, 0x24E) indicates an unexpected failure when attempting to attach a debugger using the DebugActiveProcess API. This error suggests that the operation could not be completed as expected.
Error Details
This generic error is returned by the Windows operating system when it encounters an issue while processing a request to activate debugging for a specific process. The exact cause of this failure can vary and may depend on several factors, such as the state of the target process or the current security context.
Usage Context
Developers might encounter this error when attempting to attach a debugger to a running application programmatically using the DebugActiveProcess function. This API is commonly used in debugging scenarios where developers need to inspect and modify the state of another process.
Developer Interpretation
When encountering ERROR_DEBUG_ATTACH_FAILED, it is important for developers to understand that this error does not provide specific details about why the operation failed. The developer should review the context in which the API was called, validate input parameters, and ensure that the target process is in a state that allows debugging.
Related Errors
ERROR_DEBUG_NO_ATTACH(0x406D138F): Indicates that the debugger could not attach to the specified process due to permissions or other issues.ERROR_DEBUG_PROCESS_TERMINATED(0x406D1392): The target process has terminated, preventing debugging operations from being performed.
FAQ
Q: What does ERROR_DEBUG_ATTACH_FAILED mean?
A: It indicates an unexpected failure when attempting to attach a debugger using the DebugActiveProcess API. This error is generic and may have various causes.
Q: How can I troubleshoot this issue?
A: Review the context in which the API was called, validate input parameters, and ensure that the target process is in a state that allows debugging.
Summary
The ERROR_DEBUG_ATTACH_FAILED error (590, 0x24E) signifies an unexpected failure when attempting to attach a debugger using the DebugActiveProcess API. Developers should focus on validating input parameters and ensuring the correct context for debugging operations.