How to fix dpkg: error: version string has embedded spaces in APT

First, determine which package is causing the error. Run the command that triggers the error and note the exact error message:

sudo apt update

Or if installing a specific package:

sudo apt install package-name

The error message will show the exact version string with spaces. For example:

dpkg: error: version 'uname -r' has bad syntax: version string has embedded spaces

This tells you the version field contains the literal string "uname -r" (with a space) instead of the kernel version.

If you are installing a local .deb file you created or downloaded, extract and inspect its control file:

cd /tmp
ar x /path/to/package.deb
tar -xzf control.tar.gz
cat control

Look for the Version field:

Package: mypackage
Version: 1.0.0
Architecture: amd64

The Version field must not contain any spaces and must start with a digit or epoch number. Valid version examples:
- 1.0.0
- 1:9.10.3.dfsg.P4-12.3+deb9u4
- 2020.12.16~dfsg-1~ubuntu~20.04.1

If the version contains spaces, you must fix the source and rebuild the .deb file correctly.

If the error comes from a system package (from apt repositories), check the dpkg database:

sudo cat /var/lib/dpkg/status | grep -A 20 "Package: problematic-package-name"

Look at the Version line. It should be clean without spaces:

Version: 1.2.3-4~ubuntu1

If it shows something like "Version: uname -r" or has embedded spaces, the package metadata is corrupted.

You can also query installed packages:

dpkg -l | grep problematic-package

If you are building your own .deb package, check your debian/control or debian/rules file. Look for any backtick issues:

Wrong (using single quotes):

echo "Version: 'uname -r'" > control

Correct (using backticks):

echo "Version: $(uname -r)" > control

Or better, hardcode the version:

echo "Version: 5.15.0-56-generic" > control

Rebuild the .deb file:

cd /path/to/package
dpkg-deb --build . ../package.deb

Then test installation:

sudo dpkg -i ../package.deb

Use dpkg's built-in validation to check if a version string is valid (requires dpkg 1.18.16+):

dpkg --validate-version "1.0.0"
echo $?

Return codes:
- 0 = valid version
- 1 = invalid but might work in lax contexts
- 2 = invalid and will definitely fail

Test your version:

dpkg --validate-version "uname -r"
# Returns 2 (invalid)

dpkg --validate-version "5.15.0-56"
# Returns 0 (valid)

Use this to verify any custom version strings before creating packages.

If the error comes from a system package and is due to corruption in /var/lib/dpkg/status:

# Create a backup first
sudo cp /var/lib/dpkg/status /var/lib/dpkg/status.backup

# Reconfigure packages
sudo dpkg --configure -a

If a specific package is broken:

# Remove the broken package
sudo dpkg --remove --force-remove-reinstreq broken-package-name

# Reinstall it
sudo apt install --reinstall broken-package-name

If corruption is severe:

# Clear the available database and rebuild
sudo dpkg --clear-avail
sudo apt update

# Reconfigure all packages
sudo dpkg --configure -a

After fixing the version string or package metadata, test that dpkg accepts it:

sudo apt update

If installing a specific package:

sudo dpkg -i /path/to/fixed-package.deb

Or using apt:

sudo apt install package-name

Check package status:

dpkg -l | grep package-name
sudo dpkg -s package-name

If the error still occurs, double-check the version field one more time:

dpkg -I /path/to/package.deb | grep Version

The version must be a single string with no spaces.