How to fix dpkg: error: unable to create new file 'path': Permission denied in APT

The simplest and most common fix is to run your command with sudo prefix:

sudo apt update
sudo apt install package-name
sudo apt upgrade
sudo dpkg -i package.deb

This grants the necessary root privileges to modify protected system directories. If you forget sudo and the command fails, just rerun it with sudo.

If you already used sudo but still see the error, another package manager might be using dpkg. Check for active processes:

sudo lsof /var/lib/dpkg/lock-frontend
sudo lsof /var/lib/apt/lists/lock
sudo lsof /var/cache/apt/archives/lock

If any processes are listed, they must complete first. If you see a process that shouldn't be running, you can kill it:

sudo kill -9 <PID>

Common culprits include Software Center, Software Updater, Synaptic, or unattended-upgrades.

If no processes are using dpkg but lock files still exist, they may be stale from an interrupted operation. Remove them:

sudo rm /var/lib/dpkg/lock
sudo rm /var/lib/dpkg/lock-frontend
sudo rm /var/lib/apt/lists/lock
sudo rm /var/cache/apt/archives/lock

After removing lock files, reconfigure dpkg:

sudo dpkg --configure -a
sudo apt update

This forces dpkg to check and complete any pending operations.

If the problem persists, the /var/lib/dpkg or /var/cache/apt directories may have incorrect ownership. Restore proper permissions:

sudo chown -R root:root /var/lib/dpkg
sudo chown -R root:root /var/cache/apt
sudo chmod 755 /var/lib/dpkg
sudo chmod 755 /var/cache/apt

Then try your package operation again:

sudo apt update

This ensures these critical directories are owned by root and have the correct read/write/execute permissions.

If you've had interrupted downloads, clean the cache and start fresh:

sudo apt clean
sudo apt autoclean
sudo apt update
sudo apt install package-name

The apt clean command removes all cached .deb files, while autoclean removes only outdated ones. This resolves issues with corrupted or incomplete package downloads.

In rare cases, the error occurs if /var is mounted read-only or if the disk is full:

df -h /var
mount | grep "on /var"

If /var is full, delete old log files:

sudo journalctl --vacuum=50M
sudo rm /var/log/*.old

If /var is mounted read-only, remount it as read-write:

sudo mount -o remount,rw /var