Recently I switched to Manjaro, but I still need from time to time work with some windows only programs, so I decided to use QEMU/KVM with virt manager and so far everything was fine except after installing libguestfs using sudo pacman -Sy libguestfs I noticed that there is no virt-filesystems command. I also checked if I installed something wrong, but guestmount is an avalible command so I don’t why that one is not working.
Also except that I got stuck a little bit at networking, while I managed to get internet working in my windows VM, it was using NAT which is not the most comfortable configuration for the task I will need it to do, so I tried configuring it to Bridge but it just throws Error starting domain: Cannot get interface MTU on 'win10vm': No such device.
Since the package libguestfs doesn’t provide the guestfs-tools anymore, you can’t install it form the normal repository. There is an AUR package that provides the tools and is called guestfs-tools , but it is know for build problems. You might not be able to install it.
But as @Nachlese said, try guestmount. It is part of the libguestfs package.