Kaleido export fails intermittently in Plotly 6.x / Python 3.14 environment

[berkdemir]

Description

plotly.io.to_image(..., engine="kaleido") raises:

ValueError: Image export using the "kaleido" engine requires the Kaleido package

even though Kaleido is installed and importable.

The issue disappears after downgrading Plotly and Kaleido.

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Environment

• Python: 3.14.4 (Windows 11)
• Plotly: 6.7.0 (initial issue) → works after downgrade
• Kaleido: 1.2.0 (initial) → works after downgrade
• OS: Windows 11

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Steps to reproduce

import plotly.graph_objects as go
import plotly.io as pio

fig = go.Figure(data=[go.Bar(y=[1, 2, 3])])

img = pio.to_image(fig, format="png", engine="kaleido")

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Expected behavior

PNG image should be generated via Kaleido without errors.

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Actual behavior

ValueError: Image export using the "kaleido" engine requires the Kaleido package

despite Kaleido being installed.

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Workaround

pip install plotly==5.24.1 kaleido==0.2.1

After downgrade, image export works as expected.

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Notes

This seems related to runtime compatibility / engine registration between:

• Plotly 6.x
• Kaleido 1.x
• Python 3.14 (Windows)

Possibly related to how Kaleido engine is registered in Plotly at runtime.

[emilykl]

Hi @berkdemir, thanks for reporting. I wasn't able to reproduce the issue on Mac. I will test on a Windows machine next week.

In the meantime, could you post the full stack trace of the error?