I could not see applications when I opened Software Center. When I tried to reinstall I got an error message:

E: Could not get lock /var/lib/dpkg/lock-frontend. It is held by process 8394 (apt-get)
N: Be aware that removing the lock file is not a solution and may break your system.
E: Unable to acquire the dpkg frontend lock (/var/lib/dpkg/lock-frontend), is another process using it?

Please help me resolve the above issue.

  • 1
    Check you haven't a terminal session open performing a package operation (esp. waiting for you to answer a question such as a Y to proceed)
    – guiverc
    Jun 11, 2021 at 3:19

1 Answer 1


Explore with ps -fp8394. If process 8394 exists, you (or unattended-updates) are updating the packaging system elsewhere.

If process 8394 does not exist, the lock file may be left over from an update interrupted by a sudden reboot. If so, it should be deleted, BUT your packaging system may be in an inconsistent state.


sudo apt update
sudo apt upgrade

and Read the Error Messages.

An alternative explanation for ps -fp8394 being empty may be that process 8394 has finished, and deleted the lock file.

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