failed to copy files to image

Hi,
I was about to create a new kvm and I got this message when generating the image: failed to copy files to image.
This was supposed to be my second kvm on a 5.19 x86 with 10240MB size. The first one with 4096MB worked fine.
But now no other size works anymore, tried with 64MB, 128MB, 1024MB etc.

What to do now?

Thanks,
Andras