Hi, I'm about to repair my GRUB bootloader as I speak using the Boot Repair tool in Ubuntu. So far I have typed the following into the terminal to get the tool:

sudo add-apt-repository ppa:yannubuntu/boot-repair
sudo apt-get update
sudo apt-get install -y boot-repair && boot-repair

At a certain point the Boot Repair tool told me to enter into the terminal:

sudo chroot "/mnt/boot-sav/sdc3" apt-get install -y --force-yes grub-pc

But the problem is later on I get the message"

Running in chroot, ignoring request.
Processing triggers for ureadahead (0.100.0-19) ...
W: --force-yes is deprecated, use one of the options starting with --allow instead.

Thanks.

Edit: Well I just removed the "--force-yes" part of the command and I managed to get it to work. Still, I wouldn't mind getting some explanation about it as I literally know nothing about Linux.

have no idea why you want to chroot into your system if it is running just run the run the sudo grub-install /dev/sda if that is the drive you boot from. to the device you want. then run sudo grub-mkconfig -o /boot/grub2/grub.cfg or

grab your live cd boot it and do a. it will read your drives and . omg ubuntu makes it seem so hard. Grub rescue tools all that crap.
if in a live cd make sure you grub-mkconfig -o path/to/device/boot/grub2/grub.cfg
if you still have your grub folder on your system no need to grub-mkconfig.
the grub probe will look for grubs. ubuntu makes it so confusing.
pop a live cd in and use the boot a partiton option and then run grub-install.

I agree with Drakeo that Ubuntu makes things seem more difficult than they are.

And can you clarify your current setup including whether or not you are chrooted into your system?

Are you running a live cd right now trying to repair?

Ubuntu is having you use a PPA which is a nonstandard repository and adding it to your tools then running that tool. The command seems to indicate you are running a live cd and it is repairing boot, indicated by the "chroot" and that paths are prefixed with /mnt.

The indicates that you are being advised to use a deprecated (meaning no longer supported) command argument and then indicates of the new proper way to do what "--force-yes" used to do.

When you are having boot problems with Grub and have the boot repair tool, your best option is to NOT try to repair but to run with the option to Create Bootinfo Summary and post a link to it here. That way, people with more knowledge will be able to review the output and give you some advice.