Hi all, I've found an issue with virt-sparsify on Centos 6.3 with it's image format detection. If I take a qcow2 image and attempt to sparsify it with... virt-sparsify -v centos6.3-gold.img centos6.3-gold.img-sparsified ... it creates a raw file as it's output rather than a qcow2 file. In the man page it says that the format should be preserved. In the log I can see: qemu-img convert -f qcow2 -O 'raw' '/tmp/sparsifycfbc31.qcow2' 'centos6.3-gold.img-sparsified' However, if I manually set the input format and output format then it works fine.... virt-sparsify -v --format qcow2 --convert qcow2 centos6.3-gold.img centos6.3-gold.img-sparsified In the log I get: qemu-img convert -f qcow2 -O 'qcow2' '/tmp/sparsify2e15e4.qcow2' 'centos6.3-gold.img-sparsified' I have version 1.16.19-1 of libguestfs-tools installed. I have also tried on an Ubuntu system running an older version of the tools, and it doesn't seem to have this problem. Regards, Paul Maunders