This error occurs when trying to install a Debian package built for a different CPU architecture than your system. Enabling multiarch support with dpkg --add-architecture allows you to install packages from different architectures on the same system.
The dpkg package manager is rejecting a package installation because the package binary (i386) is compiled for a different architecture than what your system uses (amd64). This is a safety check to prevent installing incompatible binaries. Modern Linux systems can support multiple architectures simultaneously through a feature called multiarch, which allows installing and running 32-bit applications on 64-bit systems and vice versa.
First, verify what architecture your system is running:
dpkg --print-architectureThis shows your primary architecture (amd64 for 64-bit). You can also check registered foreign architectures with:
dpkg --print-foreign-architecturesAdd support for the foreign architecture (typically i386 for 32-bit on amd64):
sudo dpkg --add-architecture i386For other architectures, replace i386 with arm, arm64, armhf, etc. as needed. This tells dpkg to accept packages from multiple architectures.
After adding a new architecture, update the package lists:
sudo apt-get updateThis rebuilds the package cache to include packages from all registered architectures.
Now you can install the package. If installing from a .deb file:
sudo dpkg -i package.debOr using apt-get, specify the architecture explicitly:
sudo apt-get install package:i386The package should now install without architecture mismatch errors.
Multiarch enables running binaries of different architectures on the same system by installing architecture-specific runtime libraries alongside the native libraries. Important considerations: (1) Library packages (libc6, libssl, etc.) can coexist for multiple architectures, but application packages often conflict - you may need to uninstall one architecture version before installing another; (2) Development packages (-dev) typically conflict between architectures; you only need the -dev packages for building, not running; (3) Third-party repositories may not support all architectures - add architecture restrictions to /etc/apt/sources.list using [arch=amd64] syntax if needed; (4) The --force option (dpkg --force architecture -i package.deb) can override this check but may break dependencies - use only as a last resort.
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