How to fix E: Could not open file /var/lib/dpkg/status - open (13: Permission denied) in APT

The most common fix is to simply prefix your apt command with sudo:

sudo apt update
sudo apt install package-name
sudo apt-get upgrade

The sudo command grants you temporary root/superuser privileges needed to access the dpkg database. Without it, your regular user account cannot read the protected system files.

Another process might be holding a lock on the dpkg database. Check if any other apt or package manager is running:

sudo lsof /var/lib/dpkg/lock-frontend

If output is shown, wait for that process to complete. You can also check:

sudo lsof /var/lib/dpkg/lock
sudo lsof /var/cache/apt/archives/lock

If you see a process ID, you can wait for it to finish or carefully terminate it with:

sudo kill -9 <PID>

If no process is using the locks, stale lock files might be blocking access. Remove them:

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

Then reconfigure the dpkg database:

sudo dpkg --configure -a
sudo apt update

If the issue persists, the dpkg directory permissions may be incorrect. Fix them:

sudo chown root:root /var/lib/dpkg
sudo chmod 755 /var/lib/dpkg
sudo chown root:root /var/lib/dpkg/status
sudo chmod 644 /var/lib/dpkg/status

These commands ensure the dpkg directory and status file are owned by root with the correct permissions.

If the status file is corrupted, restore it from the automatic backup:

sudo cp /var/backups/dpkg.status.0 /var/lib/dpkg/status
sudo apt update

Alternatively, if that backup doesn't exist, try:

sudo cp /var/lib/dpkg/status-old /var/lib/dpkg/status
sudo apt update

If a package installation was interrupted, reconfigure broken packages:

sudo dpkg --configure -a
sudo apt --fix-broken install

This attempts to complete any incomplete package configurations and fixes dependencies.