This article applies to all MetaDefender Sandbox releases deployed on Linux Ubuntu systems.
When should you use this?
apt update fails with “Hash Sum mismatch” and the installer exits with code 100.
- Cleaning /var/lib/apt/lists and caches removes stale metadata that causes checksum mismatches.
- Switching mirrors avoids mid-sync index/hash changes.
- Acquire::* options add retries and send cache-control headers to defeat stale proxies.
Likely causes
- Stale APT metadata or cached indexes
- Mirror drift (repository updated mid-sync)
- Caching proxy serving old indexes
How to fix
- Clean APT metadata & caches, then refresh
sudo rm -rf /var/lib/apt/lists/*``sudo apt-get clean``sudo apt-get autoclean
sudo apt-get update \``-o Acquire::Retries=5 \``-o Acquire::http::No-Cache=true \``-o Acquire::https::No-Cache=true \``-o Acquire::CompressionTypes::Order::=gz
- Switch to a known-good mirror
Backup sources list
sudo cp /etc/apt/sources.list /etc/apt/sources.list.bak
Switch archive + security to Azure (choose any stable, close mirror)
sudo sed -Ei 's|http://(archive|security).ubuntu.com/ubuntu|http://azure.archive.ubuntu.com/ubuntu|g' /etc/apt/sources.list
Refresh after switching mirrors
sudo rm -rf /var/lib/apt/lists/*``sudo apt-get update
- If behind a Proxy, soft-bypass cache for Ubuntu domains
sudo apt-get update \``-o Acquire::http::No-Cache=true \``-o Acquire::http::No-Store=true \``-o Acquire::https::No-Cache=true
If Further Assistance is required, please proceed to log a support case or chat with one of our support engineers.
