ERROR_OFFLOAD_WRITE_FLT_NOT_SUPPORTED - 4441 (0x1159)
The copy offload write operation is not supported by a filter.
Updated: Feb 21, 2026
Technical Meaning
This error code indicates that a filter driver does not support the copy offload write operation. Copy offload is a feature in Windows that allows data to be written directly from user space to a storage device, bypassing the file system cache.
Error Details
The ERROR_OFFLOAD_WRITE_FLT_NOT_SUPPORTED error code (4441 or 0x1159) is returned when an attempt is made to perform a copy offload write operation and the filter driver in use does not support this feature. This can occur during file operations that involve direct data transfer from user space to storage.
Usage Context
This error typically occurs in scenarios where the operating system attempts to utilize copy offload capabilities, such as when writing large files or performing bulk data transfers. The presence of a filter driver that does not support this feature can prevent the operation from being completed successfully.
Developer Interpretation
Developers should be aware that certain filter drivers may not support all file system operations, including copy offload write. When encountering this error, it is important to ensure that the appropriate filters are installed and configured correctly for the intended use case. Additionally, developers should verify that their application logic handles such errors gracefully, as they can impact performance and data integrity.
Related Errors
- ERROR_NOT_SUPPORTED (0x00000001)
- ERROR_INVALID_FUNCTION (0x00000047)
These related errors may also indicate that a specific operation is not supported by the current system configuration or driver setup.
FAQ
Q: What does this error mean?
A: This error indicates that the filter driver in use does not support copy offload write operations.
Q: How can I resolve this issue?
A: Ensure that the correct filters are installed and configured to support copy offload. If necessary, consult the documentation for the specific filter drivers being used.
Summary
The ERROR_OFFLOAD_WRITE_FLT_NOT_SUPPORTED error code (4441 or 0x1159) is a specific error indicating that a filter driver does not support the copy offload write operation. Developers should be aware of this limitation and ensure their applications handle such errors appropriately to maintain system stability and performance.