update-initramfs is stuck

Today I've also encountered this error and removing then reinstalling initramfs-tools have fixed the hangs I've been experiencing.

sudo apt remove initramfs-tools
sudo apt install initramfs-tools

In my case, it was probably some configuration or a temporary file was broken / locked for initramfs-tools.

This was on Ubuntu 18.04 so it can still happen.

Okay, I have found a workaround to fix this error.

After I executed the steps in my question, I tried to remove the kernel with:
```
sudo update-initramfs -k 3.5.0-23-generic -d
```
After a reboot GRUB showed up and selected my version of Ubuntu but when it tried to load the kernel, it said

Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block (0,0)
Then I just chrooted with a LiveCD into Ubuntu and executed:
```
sudo dpkg --configure -a
sudo apt-get install linux-image-3.5.0-25-generic
```
And after a reboot everything was OK.

Step 2 of slashcrack’s sounds largely unnecessary. Instead it should suffice to run

sudo update-initramfs -d -k <VERSION>
sudo apt-get install -f

where you replace <VERSION> with the affected kernel version string (here: 3.5.0-23-generic).

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