Krdytkyu

Trying to remove old kernels to make space for an update (currently running 16.04.03 server):

sudo apt autoremove

gives this:

Reading package lists... Done                                                   

Building dependency tree                                                        

Reading state information... Done                                               

You might want to run â??apt-get -f installâ?? to correct these.                

The following packages have unmet dependencies.                                 

 linux-headers-generic : Depends: linux-headers-4.4.0-141-generic but it is not 

installed                                                                       

E: Unmet dependencies. Try using -f.

So, I run:

sudo apt -f autoremove

Doing so brings this:

The following additional packages will be installed:

Reading package lists...

Building dependency tree...

Reading state information...

Correcting dependencies... Done

The following additional packages will be installed:

  linux-headers-4.4.0-141 linux-headers-4.4.0-141-generic

The following packages will be REMOVED

  linux-headers-4.4.0-109 linux-headers-4.4.0-112 linux-headers-4.4.0-116

  linux-headers-4.4.0-119 linux-headers-4.4.0-127 linux-headers-4.4.0-128

  linux-headers-4.4.0-130 linux-headers-4.4.0-130-generic

  linux-headers-4.4.0-131 linux-headers-4.4.0-131-generic

  linux-headers-4.4.0-133 linux-headers-4.4.0-133-generic

  linux-headers-4.4.0-134 linux-headers-4.4.0-134-generic

  linux-headers-4.4.0-87 linux-image-4.4.0-130-generic

  linux-image-4.4.0-131-generic linux-image-4.4.0-133-generic

  linux-image-4.4.0-134-generic linux-image-extra-4.4.0-130-generic

  linux-image-extra-4.4.0-131-generic linux-image-extra-4.4.0-133-generic

  linux-image-extra-4.4.0-134-generic

The following NEW packages will be installed

  linux-headers-4.4.0-141 linux-headers-4.4.0-141-generic

0 to upgrade, 2 to newly install, 23 to remove and 1 not to upgrade.

2 not fully installed or removed.

Need to get 0 B/10.8 MB of archives.

After this operation, 1,387 MB disk space will be freed.

Do you want to continue? [Y/n]                                                  

E: Waited for /usr/sbin/dpkg-preconfigure --apt || true but it wasn't there     

E: Failure running script /usr/sbin/dpkg-preconfigure --apt || true

/etc/apt/apt.conf.d/70debconf looks like that:

// Pre-configure all packages with debconf before they are installed.

// If you don't like it, comment it out.

DPkg::Pre-Install-Pkgs {"/usr/sbin/dpkg-preconfigure --apt || true";};

I can run

/usr/sbin/dpkg-preconfigure --help

There should be enough free space, or is that not enough?

df -h /boot                                              

Filesystem      Size  Used Avail Use% Mounted on                                

/dev/sda1       472M  106M  342M  24% /boot

I tried, as suggested by George Udosen:

sudo dpkg --configure -a

But that brings:

dpkg: dependency problems prevent configuration of linux-headers-generic:       

 linux-headers-generic depends on linux-headers-4.4.0-141-generic; however:     

  Package linux-headers-4.4.0-141-generic is not installed.                     



dpkg: error processing package linux-headers-generic (--configure):             

 dependency problems - leaving unconfigured                                     

dpkg: dependency problems prevent configuration of linux-generic:               

 linux-generic depends on linux-headers-generic (= 4.4.0.141.147); however:     

  Package linux-headers-generic is not configured yet.                          



dpkg: error processing package linux-generic (--configure):                     

 dependency problems - leaving unconfigured                                     

Errors were encountered while processing:                                       

 linux-headers-generic                                                          

 linux-generic

Just for fun, I tried the next suggested command:

sudo apt update

Which brings - after the hits:

Reading package lists... Done                                                   

E: Couldn't wait for subprocess - waitpid (10: No child processes) 

Actually, when trying solutions from other threads I saw that "No child processes" a few times.

Update: Issue solved. Actually, probably it was several.
Note: I run the server via Webmin. Some threads suggested that this is a Webmin issue, so before I posted here, I tried to fix the issue directly at the server, but wasn't able to do. But now ....

I found in another thread how to remove the Linux packages that create the problems:

sudo dpkg -P linux-generic

sudo dpkg -P linux-image-generic

sudo dpkg -P linux-headers-generic

That, combined possibly with George Udosen's (thanks a lot!!!) proposals, got rid of the dependency errors and made it possible to install the latest version of Webmin.
The

E: Waited for /usr/sbin/dpkg-preconfigure --apt || true but it wasn't there     

E: Failure running script /usr/sbin/dpkg-preconfigure --apt || true

turned out to be a Webmin issue and was then gone when runing the autoremove from the server directly.

Thanks a lot for the help!
The server will stand again unattended in my empty flat for some time, so it was important to get the issue solved. I can sleep again tonight.