# CrewAI memory recall: "TypeError: can't subtract offset-naive and offset-aware datetimes"

*Disclosure: I work on MemorySync (I'm Mohammed, the founder). I drafted this page with AI assistance and checked it against the GitHub issue and the crewAI source listed under Sources on Nov 10, 2026. Code status: I ran the repro and the workaround offline on crewai 1.15.39 (Python 3.13, no model calls, no network). I didn't run a full crew with memory, a custom storage backend, the fix PR linked in the issue, or any MemorySync code.*

Your crew's memory recall stops with:

```text
TypeError: can't subtract offset-naive and offset-aware datetimes
```

That's crewAI issue [#7529](https://github.com/crewAIInc/crewAI/issues/7529), "compute_composite_score crashes with TypeError on timezone-aware datetimes during memory recall". It happens when a memory record's `created_at` carries a timezone, for example `datetime.now(timezone.utc)` or a timestamp parsed from a store or API with `+00:00` or `Z`.

MemorySync doesn't fix this bug. The crash is in crewAI's own recall scoring, and you need the workaround below with or without MemorySync.

> **Skip the memory plumbing around this fix.** Once your records carry safe timestamps, the [MemorySync CrewAI guide](https://docs.memorysync.io/guides/crewai?utm_source=hashnode&utm_medium=organic_page&utm_campaign=v5_oct25&utm_content=pseo_crewai-memory-recall-cant-subtract-offset-naive-and-offset-aware-datetimes) shows how to point CrewAI's `Memory(storage=...)` at MemorySync. It doesn't change how crewAI scores records. When you're ready, [see MemorySync](https://memorysync.io/?utm_source=hashnode&utm_medium=organic_page&utm_campaign=v5_oct25&utm_content=pseo_crewai-memory-recall-cant-subtract-offset-naive-and-offset-aware-datetimes). Founding offer: use code FOUNDING30 for 30% off Starter for your first 3 months (Settings → Billing).

## Status (Nov 10, 2026)

- [#7529](https://github.com/crewAIInc/crewAI/issues/7529) was opened Sep 17, 2026 and is **open**. The reporter linked a fix PR in the thread; it isn't merged.
- It reproduces on crewai 1.15.39, the latest release on PyPI when I checked (Nov 10, 2026; uploaded Nov 9).

## Step 1: Reproduce it

The issue's repro, extended with a naive timestamp for comparison:

```python
from datetime import datetime, timezone
from crewai.memory.types import MemoryRecord, MemoryConfig, compute_composite_score

for label, ts in [("naive utc", datetime.utcnow()), ("aware utc", datetime.now(timezone.utc))]:
    rec = MemoryRecord(content="User prefers Python", created_at=ts)
    try:
        print(label, compute_composite_score(rec, 0.85, MemoryConfig()))
    except Exception as e:
        print(label, type(e).__name__, e)
```

Output on crewai 1.15.39:

```text
naive utc (0.8249999999943841, ['semantic', 'recency'])
aware utc TypeError can't subtract offset-naive and offset-aware datetimes
```

## Why it happens

In crewai 1.15.39, `lib/crewai/src/crewai/memory/types.py` computes a record's age like this:

```python
age_seconds = (datetime.utcnow() - record.created_at).total_seconds()
```

`datetime.utcnow()` returns a naive datetime. Python refuses to subtract an aware datetime from a naive one. `MemoryRecord.created_at` itself defaults to `datetime.utcnow` (naive), so records crewAI creates on its own are fine. The crash comes from records you build yourself, or from a storage backend that returns aware timestamps. Per the issue, `compute_composite_score()` runs on every `memory.recall()`, so one aware record is enough to break recall.

## Step 2: Store naive UTC timestamps

Until the fix ships, make sure every `created_at` that reaches crewAI is naive UTC, which is what crewAI's own default produces:

```python
from datetime import datetime, timezone

def to_naive_utc(d: datetime) -> datetime:
    if d.tzinfo is None:
        return d  # assume it's already UTC, like crewAI's default
    return d.astimezone(timezone.utc).replace(tzinfo=None)

rec = MemoryRecord(content="User prefers Python", created_at=to_naive_utc(datetime.now(timezone.utc)))
print(compute_composite_score(rec, 0.85, MemoryConfig()))
```

This ran without error on crewai 1.15.39. Where to apply it:

- **Records you create yourself:** pass `created_at=to_naive_utc(...)`, or leave `created_at` out and let crewAI use its default.
- **A custom storage backend:** convert timestamps on the way out, in the code that builds `MemoryRecord` objects from your database rows. Postgres `timestamptz`, ISO strings ending in `Z`, and many client libraries give you aware datetimes.
- **Timestamps parsed from strings:** `datetime.fromisoformat("2026-10-30T10:00:00+00:00")` is aware. Run it through `to_naive_utc` too.

If any of your naive timestamps are in local time rather than UTC, convert them first; otherwise the recency part of the score will be off by your UTC offset.

## Step 3: Find the record that breaks recall

If recall already fails, look for records whose `created_at` has a `tzinfo`:

```python
bad = [r for r in records if r.created_at.tzinfo is not None]
```

How you list `records` depends on your storage backend. Rewriting those timestamps with `to_naive_utc` and saving them again removes the crash.

## Skip the plumbing with MemorySync

Disclosure: I build MemorySync.

This doesn't change the fix above: the crash is in crewAI's own scoring, so keep `created_at` naive UTC as in Step 2. The [MemorySync CrewAI guide](https://docs.memorysync.io/guides/crewai?utm_source=hashnode&utm_medium=organic_page&utm_campaign=v5_oct25&utm_content=pseo_crewai-memory-recall-cant-subtract-offset-naive-and-offset-aware-datetimes) documents `MemorySyncStorage`, a CrewAI `StorageBackend` you pass as `Memory(storage=...)`, so the crew's save and recall loop runs against MemorySync instead of local LanceDB files. It requires crewai 1.0+ and Python 3.10+ and lists `crewai-memorysync` 1.1.0. The guide doesn't say whether this changes how crewAI scores recalled records, so don't count on it to avoid this error.

From the guide:

**Unverified (not run):**

```bash
pip install crewai-memorysync
```

```python
from crewai import Crew
from crewai.memory import Memory
from crewai_memorysync import MemorySyncStorage

crew = Crew(
    agents=[researcher, writer],
    tasks=[research_task, write_task],
    memory=Memory(storage=MemorySyncStorage(user_id="support-crew")),
)
crew.kickoff()
```

*Snippet adapted from the [MemorySync CrewAI guide](https://docs.memorysync.io/guides/crewai?utm_source=hashnode&utm_medium=organic_page&utm_campaign=v5_oct25&utm_content=pseo_crewai-memory-recall-cant-subtract-offset-naive-and-offset-aware-datetimes); I haven't run it for this page. Set `MEMORYSYNC_API_KEY` in the environment, as the guide says. Per the guide, `user_id` is the memory owner: one id per crew gives a shared knowledge base, one per end user gives memory per customer.*

**Try it:** MemorySync is optional here: the steps above work without it. If you want the memory layer from the snippet, [see MemorySync](https://memorysync.io/?utm_source=hashnode&utm_medium=organic_page&utm_campaign=v5_oct25&utm_content=pseo_crewai-memory-recall-cant-subtract-offset-naive-and-offset-aware-datetimes), create an API key in the dashboard and drop the snippet into your agent.

## FAQ

**Is this a problem with my embedder or LLM?**
No. The error comes from date arithmetic in the scoring step, before any model is involved. My repro ran with no model and no network.

**Why does `datetime.utcnow()` print a deprecation warning?**
It's deprecated since Python 3.12. The issue's proposed fix moves to `datetime.now(timezone.utc)` and normalises both sides to UTC.

**Will upgrading fix it?**
Not as of Nov 10, 2026. The issue is open and crewai 1.15.39 still has the naive subtraction. Watch #7529 for the merged fix.

## Sources

- github.com/crewAIInc/crewAI/issues/7529 (opened 2026-09-17, open, 4 comments; repro, root cause and proposed fix; read 2026-11-10)
- crewai 1.15.39 source: `crewai/memory/types.py` (`MemoryRecord.created_at` default, `compute_composite_score`; read 2026-11-10)
- Offline runs on crewai 1.15.39, Python 3.13 (2026-11-10)
- MemorySync CrewAI guide: docs.memorysync.io/guides/crewai (fetched 2026-10-30)

## Try it

For an overview of MemorySync, see [the MemorySync homepage](https://memorysync.io/?utm_source=hashnode&utm_medium=organic_page&utm_campaign=v5_oct25&utm_content=pseo_crewai-memory-recall-cant-subtract-offset-naive-and-offset-aware-datetimes).

**Next step:** read the [MemorySync CrewAI guide](https://docs.memorysync.io/guides/crewai?utm_source=hashnode&utm_medium=organic_page&utm_campaign=v5_oct25&utm_content=pseo_crewai-memory-recall-cant-subtract-offset-naive-and-offset-aware-datetimes), then [see MemorySync](https://memorysync.io/?utm_source=hashnode&utm_medium=organic_page&utm_campaign=v5_oct25&utm_content=pseo_crewai-memory-recall-cant-subtract-offset-naive-and-offset-aware-datetimes). Founding offer: use code FOUNDING30 for 30% off Starter for your first 3 months (Settings → Billing).