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Fix Boards Manager “DEADLINE_EXCEEDED” / timeout installing the ESP32 core

The ESP32 core is a ~500 MB download and the IDE gives up on slow connections. Raise the network timeout, retry to resume, or install over a different network.

ESP32ESP32-S3ESP32-C3Raspberry Pi PicoUpdated 3 Nov 2026

Community draft — report a mistake

What you see

OutputOutput
Downloading packages
esp32:esp-x32@2601 ...
esp32:esp-x32@2601 Downloaded 112.4 MiB / 304.6 MiB
Failed to install platform: 'esp32:esp32:3.3.12'.
Error: 4 DEADLINE_EXCEEDED: net/http: request canceled (Client.Timeout or context cancellation while reading body)

Arduino IDE 2 downloads board packages through arduino-cli, which has a time limit for each download. The ESP32 core pulls several hundred megabytes of compilers from GitHub. On a slow or unstable connection a single file can take longer than the limit, and the install stops with DEADLINE_EXCEEDED.

Retrying resumes from the next file. Raising the timeout in arduino-cli.yaml stops it happening at all.

Quick fix — try in order

  1. 1

    Click Install again

    Completed tool archives are kept in the staging folder, so each retry continues with the next file instead of starting over.

  2. 2

    Raise the network timeout

    Close the IDE and edit arduino-cli.yaml (Windows: C:\Users\<you>\.arduinoIDE\arduino-cli.yaml; Linux/macOS: ~/.arduinoIDE/arduino-cli.yaml). Add network: with connection_timeout: 1200s under it, save, reopen the IDE and install.

  3. 3

    Delete a corrupt partial download

    If it fails on the same file every time, delete that file from the staging/packages folder inside Arduino15 and retry.

  4. 4

    Try another network

    Some office, college and ISP networks throttle or block GitHub downloads, where the toolchains live. A mobile hotspot for this one install often works.

  5. 5

    Install only what you need

    Older core versions (2.0.x) are smaller. For a classic ESP32 project, an older version is fine if bandwidth is tight — but sketches on FlashReady are tested on the version shown on each page.

Why it happens

Why is the ESP32 core so big?

Core 3.x ships compilers and pre-built libraries for every ESP32 variant (ESP32, S2, S3, C3, C6, H2, P4), each several hundred MB unpacked.

DEADLINE_EXCEEDED means?

The IDE's download didn't finish within the allowed time. The network didn't fail completely; it was too slow or stalled.

Board-specific notes

Raspberry Pi Pico (Arduino-Pico): The rp2040 core also downloads large toolchains from GitHub; the same timeout setting helps.

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