How To Fix Could Not Get Lock /var/lib/dpkg/lock-frontend Error On Debian And Ubuntu

On a Linux-based Based Operating System, like Debian and Ubuntu systems that use the apt or the dpkg package manager you may run into this error. On older systems, this same error can also be displayed as could not lock /var/lib/dpkg/lock resource temporarily unavailable. Typically, package managers install and remove software one package at a time. This is done to ensure your system’s safety, dependencies, and more. The dpkg frontend lock will occur when there is more than one running process the package manager is trying to run. In this blog post, we will look at potential causes and the solution from the command line.

Possible Causes

There are quite a few possible causes for this error message, below is a list of possible causes:

• Concurrent Package Manager Operations
• Stale Lock Files
• Software Updater
• Other User Sessions
• Graphical Package Managers
• Unattended Upgrades
• Incomplete or Interrupted Package Operations
• Background Services

Before Starting

Before trying the solution we recommend trying this first.

1. Check for running package manager processes
   • Most of the time the error message is displayed because another process is running. To check to see if that is the case run the followingps aux | grep -E 'apt|dpkg'
   • If you see processes like dpkg, apt-get, or the apt command running continue to step two.
2. Wait for the existing process to complete
   • If there is a process running, give it some time to complete (in most cases 10-20 minutes should be enough).

Solution

If there isn’t a process running, or it has been running for an abnormal amount of time try the following.

1. Reboot and try again
   • First, try rebooting and try again if that doesn’t solve the issue continue to the next step.
2. Check for the process holding the lock
   • Next, check for processes interacting with /var/lib/dpkg/lock-frontend using the lsof command line tool.sudo lsof /var/lib/dpkg/lock-frontend
   • If there is a running processes process like the apt process listed, if so give it some time and see if finishes after the reboot. If that doesn’t happen move on to the next step.
   • If no process is found skip to step 4.
3. Identify and terminate processes
   • We have waited on the process before and after the reboot to no avail, we have no option to kill the process. In this example, we will kill the process by the process id.sudo kill -9 PID
4. Remove the lock file
   • At this time there is no process running, but still not working we can try to the delete lock files by running the following:sudo rm /var/lib/dpkg/lock-frontend sudo rm /var/lib/dpkg/lock
5. Reconfigure the package database
   • To confirm that everything went as expected after removing the lock files run the following:sudo dpkg --configure -a
   • If all went as expected the command should output nothing.

Conclusion

Typically, package managers install and remove software one package at a time. This is done to ensure your system’s safety, dependencies, and more. If you’re working with Debian or Ubuntu-based systems you may encounter this. Fret not with the steps in this guide the error should be easier to understand from the potential causes of the error to the solution.

Additional Links

Done reading and looking for more to read, why not check these out?

• Other Ubuntu Posts
• The Apt Wikipedia Page