[Solved] apt-get upgrade E: Could not get lock /var/lib/dpkg/lock-frontend - open (11: Resource temporarily unavailable) E: Unable to acquire the dpkg frontend lock (/var/lib/dpkg/lock-frontend), is another process ...

Any solution?

Thanks..

Quote from dleidert

There is another process updating the database. The lock prevents two processes from accessing the package database at the same time. I'd assume cron-apt is running or stalled. Just wait a few minutes or check sudo ps aux | grep apt.

sudo ps aux | grep apt gives...

Quote from dleidert

So there is already an apt-command running. That explains the lock. Please check which process created it: sudo ps -ef --forest

Edit: This will show the running processes in a tree-like output. It might also show which process was spawned by apt-get and is stalling the parent process.

How can I terminate previous running process? or just restart the server?

Quote from dleidert

Please first check what is actually stalling by the command I gave you.

I attached output of the command. I do not know how to evaluate the result. Can you please check the attachment?

Quote from dleidert

The output does not contain any sign of a running apt command. I'd guess that apt has finished and removed the lock. The original message should not appear at the moment and you should be able to run the update from the GUI.

still gives error.

Quote from dleidert

Yes, but now it clearly says that dpkg got interrupted and what to do in this case. I'd suspect you did kill the process or restarted the system although I told otherwise. Correct?

Now you have to run:

sudo dpkg --configure -a

sudo apt-get install -f

and then I would reinstall the affected packages:

sudo apt-get install --reinstall certbot python3-certbot-dns-cloudflare

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After running sudo dpkg --configure -a

now whıch option should be selected. I am not sure which one including grub..:(

last check box?

Quote from dleidert

Check the device from which you boot. Which device is checked for the master boot record when your system boots? Don't check the partition.

Thank you, finally it worked. I upgraded to latest version.