Now older versions of qemu-kvm didn't throw this error say if you just had "-video cirrus" when starting qemu-kvm. But newer versions do care.
And this probably only applies to you if you are running from bash/terminal with remote kvm images.
What you need to do is remove the "-video" part and just add -vnc :5
eg. this would fix the error:
qemu-system-x86_64 -enable-kvm -boot order=cd,once=dc -m 1024 -drive........
The strange thing is that usually the first install or two will work on any new machine but then it suddenly won't. I had this experience on QEMU 2.13 on a different machine. There is something finicky or buggy about the CUCM installer even when choosing the same virtual hardware specs.
QEMU PC emulator version 0.12.1 (qemu-kvm-0.12.1.2-2.506.el6_10.1), Copyright (c) 2003-2008 Fabrice Bellard
WARNING: Image format was not specified for '/mnt/space/cucm12.img' and probing guessed raw.
Automatically detecting the format is dangerous for raw images, write operations on block 0 will be restricted.
Specify the 'raw' format explicitly to remove the restrictions.
#you should manually specify the format