The 'unexpected disconnect while reading sideband packet' error occurs when Git's network connection is interrupted during a fetch or clone operation. This typically indicates network instability, large repository issues, or buffer configuration problems.
The "fatal: fetch-pack: unexpected disconnect while reading sideband packet" error in Git indicates that the connection to the remote repository was unexpectedly terminated while Git was receiving data through its sideband communication protocol. When you clone or fetch from a remote repository, Git uses a protocol called "fetch-pack" to request and receive packfiles containing repository objects. The sideband protocol multiplexes different types of data (packfile data, progress information, and error messages) over a single connection. When the connection drops unexpectedly mid-transfer, Git reports this error because it was waiting to read more data from the sideband channel but the connection closed. This error is particularly common when working with large repositories, on unstable network connections, or when the Git server terminates the connection due to timeouts or resource limits. Unlike authentication errors, this indicates that communication began successfully but failed partway through the transfer.
The most reliable fix is to first do a shallow clone, then fetch the rest:
# Clone with depth 1 (only latest commit)
git clone --depth 1 <repository-url>
# Enter the repository
cd <repository-name>
# Fetch remaining history
git fetch --unshallowThis approach works because if the shallow clone fails, Git removes the incomplete directory. But if git fetch --unshallow fails, the objects already fetched remain, so you can retry until all objects are retrieved.
Increase the HTTP buffer and pack-related settings:
# Increase HTTP post buffer to 150MB
git config --global http.postBuffer 157286400
# Configure pack memory limits
git config --global core.packedGitLimit 512m
git config --global core.packedGitWindowSize 512m
git config --global pack.deltaCacheSize 2047m
git config --global pack.packSizeLimit 2047m
git config --global pack.windowMemory 2047mFor very large repositories, you may need even larger values:
git config --global core.packedGitLimit 1024m
git config --global core.packedGitWindowSize 1024mDisabling compression can help with network-related issues:
# Disable compression
git config --global core.compression 0
# Then try cloning again
git clone <repository-url>After successfully cloning, you can re-enable compression:
git config --global --unset core.compressionSSH connections can be more stable than HTTPS for large transfers:
# Convert HTTPS URL to SSH
# Instead of: https://github.com/user/repo.git
# Use: [email protected]:user/repo.git
git clone [email protected]:user/repo.gitEnsure you have SSH keys configured:
# Generate SSH key if needed
ssh-keygen -t ed25519 -C "[email protected]"
# Add to SSH agent
eval "$(ssh-agent -s)"
ssh-add ~/.ssh/id_ed25519
# Add the public key to your GitHub/GitLab account
cat ~/.ssh/id_ed25519.pubReducing the pack window can help with memory-constrained systems:
git config --global pack.window 1This reduces memory usage during pack operations at the cost of slightly larger pack sizes. Try cloning again after setting this.
Older Git versions may have bugs that cause this issue:
# Check current version
git --version
# Update on Ubuntu/Debian
sudo add-apt-repository ppa:git-core/ppa
sudo apt update
sudo apt install git
# Update on macOS with Homebrew
brew upgrade git
# Update on Windows
git update-git-for-windowsGit version 2.47 and later have various network-related fixes.
WiFi driver issues, especially with Intel and Killer WiFi adapters, can cause this error:
Windows:
1. Open Device Manager
2. Expand "Network adapters"
3. Right-click your WiFi adapter
4. Select "Update driver"
5. Choose "Search automatically for drivers"
Linux:
# Check your WiFi driver
lspci -k | grep -A 3 -i "network"
# Update firmware (Ubuntu/Debian)
sudo apt update
sudo apt install linux-firmware
sudo rebootAs a workaround, try using a wired Ethernet connection or mobile hotspot.
If using PuTTY as your SSH client on Windows, switch to OpenSSH:
# Remove GIT_SSH environment variable if set
[Environment]::SetEnvironmentVariable("GIT_SSH", $null, "User")
# Verify OpenSSH is being used
ssh -VRestart Git Bash or your terminal after making this change.
### Understanding the Sideband Protocol
The sideband protocol in Git multiplexes three channels over a single connection:
- Sideband 1: Packfile data (the actual repository objects)
- Sideband 2: Progress information (normally printed to stderr)
- Sideband 3: Error messages from the server
When you see "unexpected disconnect while reading sideband packet," Git was in the middle of reading from one of these channels when the connection terminated.
### Large Files and Git LFS
If your repository contains large files (over 100MB), consider using Git Large File Storage (LFS):
# Install Git LFS
git lfs install
# Track large files
git lfs track "*.psd"
git lfs track "*.zip"If large files are already in history, you may need to rewrite history to remove them or migrate to LFS.
### Docker and Container Environments
Cloning large repositories inside Docker containers over HTTPS is particularly prone to this error. Consider:
- Using SSH instead of HTTPS
- Mounting the repository from the host instead of cloning inside the container
- Using --depth 1 for CI/CD pipelines that don't need full history
### Proxy and VPN Considerations
Corporate proxies and VPNs may terminate long-running connections. Try:
- Configuring Git to use the proxy properly: git config --global http.proxy http://proxy:port
- Temporarily disconnecting from VPN for the clone operation
- Using SSH instead of HTTPS (SSH typically bypasses HTTP proxies)
### WSL-Specific Issues
When using Git in Windows Subsystem for Linux (WSL), network configuration issues can cause this error:
- Ensure WSL is updated: wsl --update
- Try cloning from Windows Git instead of WSL Git
- Check that DNS resolution is working properly in WSL
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