After having stopped virtual-manager, I can't use command line QEMU: “Failed to get shared ”write“ lock Is another process using the image”

[gustavklopp]

    Hi!
      I've launched a virtual image through the software virtual-manager
      (it's a GUI allowing to launch your virtual images).
      
      I've stopped normally the image and close the software
      virtual-manager.
      
      But now, I can't use QEMU directly in commandline to start this
      virtual image (by doing qemu-system-x86_64 ....):
      
      Failed to get shared "write" lock
      Is another process using the image [./ubuntu.qcow2]?
      
      I've tried to restart, I've stopped any services:  sudo
        systemctl stop virtlogd.service && sudo systemctl stop
        libvirtd.service.
      
      I've checked also the permissions (but it doesn't seem to be
      related):
      
      -rw------- 1 thephi thephi  21G jul 10 05:24 ubuntu.qcow2
      
      Thanks!