---
title: "Discussion on \"CrewAI memory + checkpointing: fixing 'Unable to serialize unknown type: ModelMetaclass' (no checkpoint written)\" | Hashnode"
description: "Discussion on \"CrewAI memory + checkpointing: fixing 'Unable to serialize unknown type: ModelMetaclass' (no checkpoint written)\". Turn on Memory and checkpointing together and every task_completed checkpoint silently fails to write. Here's why, how to catch it, and a small patch until the fix ships."
url: "https://hashnode.com/posts/crewai-memory-checkpoint-unable-to-serialize-unknown-type-modelmetaclass/6af7368de0761f91261ee465"
---

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# [CrewAI memory + checkpointing: fixing 'Unable to serialize unknown type: ModelMetaclass' (no checkpoint written)](https://memorysync.hashnode.dev/crewai-memory-checkpoint-unable-to-serialize-unknown-type-modelmetaclass?utm_source=hashnode&utm_medium=feed)

Turn on Memory and checkpointing together and every task\_completed checkpoint silently fails to write. Here's why, how to catch it, and a small patch until the fix ships.

4h ago · 11 min read · memorysync.hashnode.dev  
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Building MemorySync (memorysync.io) — persistent memory infrastructure for AI agents, Cursor, and Claude Code.

Building MemorySync (memorysync.io) — persistent memory infrastructure for AI agents, Cursor, and Claude Code.

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