APT Update Failing with “File has unexpected size. Mirror sync in progress?” on ubuntu2004 CUDA Repo (July 2025)

Accelerated Computing CUDA CUDA Setup and Installation
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Hi,

I am encountering a persistent error when running apt-get update against the NVIDIA CUDA repository for Ubuntu 20.04:

E: Failed to fetch https://developer.download.nvidia.com/compute/cuda/repos/ubuntu2004/x86_64/Packages.gz      File has unexpected size (2731565 != 2729198). Mirror sync in progress? [IP: 2.23.97.240 443]   Hashes of expected file:    - Filesize:2729198 [weak]    - SHA256:8016001c50e96aff2e638b7664e312e0fe2a51efeafd36aae798c1d443603fc8    - SHA1:15dd8e4febc82691fae53c423ce1ec7d3cd61b01 [weak]    - MD5Sum:01cf0833f2bea362efc1a4150e68087f [weak]   Release file created at: Tue, 22 Jul 2025 19:06:30 +0000   E: Some index files failed to download. They have been ignored, or old ones used instead.

This error started occurring on July 24, 2025, and has persisted through multiple retries over several hours. I understand from other reports that this may be related to repository synchronization or mirror update issues on NVIDIA’s side.

  • I am using the official Ubuntu 20.04 CUDA repository, installed via the official cuda-keyring_1.0-1_all.deb package.
  • My environment is a Docker image based on python:3.8.10, targeting Ubuntu 20.04 CUDA packages.

Could you please confirm if this is currently a known synchronization issue on your mirrors? Is there an estimate on when the repository will be fully synced and stable again? Any advice for workarounds or steps I can take to avoid build failures in the meantime would be highly appreciated.

Thank you very much for your assistance.

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