Python BufferError — What It Means & How to Fix It

What Does This Error Mean?

BufferError is raised when something goes wrong with a buffer operation. A buffer in Python is a block of raw memory that data can be read from or written to directly — used for fast data processing without making copies. You will usually see BufferError when you try to do something with a buffer that is not allowed, like trying to resize a bytes object while something else is reading from it.

Affected Models

Python 2.x
Python 3.x
All Python versions

Common Causes

Trying to resize a bytearray while an existing memoryview is pointing to it
Attempting to modify a read-only buffer
A C extension or library tried to perform an unsupported buffer operation
Calling del on a bytearray or bytes object while a memoryview holds a reference to it
Using numpy or similar libraries with incompatible buffer shapes or formats

How to Fix It

If the error says 'cannot resize an array that is exporting buffers', release any memoryview objects that reference the array before resizing it.

A memoryview keeps a live reference to the underlying buffer. While that reference exists, you cannot resize or delete the buffer.
To release a memoryview, call .release() on it explicitly: mv.release() — or use it inside a with statement which releases it automatically when the block ends.

Example: with memoryview(my_bytes) as mv: do_something(mv) — the memoryview is automatically released when the with block finishes.
If you are working with numpy arrays, check that you are not holding a view of an array and trying to resize the original at the same time.

In numpy, a 'view' is similar to a memoryview — it points directly to the same memory. Resizing the original while a view exists causes problems.
If you are writing a C extension or using ctypes, make sure your buffer objects are compatible — same format, same element size, and the correct flags (read-only vs writable).

This is advanced territory. If you are not writing C extensions yourself, this is likely a bug in a third-party library — check that library's issue tracker.
If the BufferError comes from a third-party library, update the library to the latest version — buffer handling bugs are commonly fixed in updates.

Run: pip install --upgrade library-name to get the latest version.

When to Call a Professional

BufferError is uncommon in everyday Python code. It usually appears in code that works with raw binary data, C extensions, or performance-sensitive numeric libraries like numpy. If you are seeing it, focus on releasing any memoryview objects before trying to resize or delete the underlying buffer.

Frequently Asked Questions

What is a buffer in Python?

A buffer is a region of raw memory used to temporarily hold data while it is being moved or processed. In Python, the buffer protocol lets objects expose their internal memory directly — so other code can read or write it without making a copy. This is used in performance-sensitive code like image processing, networking, and scientific computing.

What is a memoryview?

A memoryview is a Python object that lets you access the memory of another object (like bytes or bytearray) directly, without copying the data. It is very efficient for large data but creates a restriction — you cannot resize or delete the original object while the memoryview is active. Always release memoryviews when you are done with them.

Is BufferError common for beginners?

No — BufferError is uncommon in typical Python code. You are most likely to encounter it when working with binary data, C extensions, or libraries like numpy, Pillow, or struct. If you are just starting out with Python and see this error, it probably came from a library — updating the library often fixes it.