The live system creation is aborted!

I got this error when I include user data files while creating the live images.
It worked fine when I didn't include user data files.

I opened the program in terminal by

DBGLEV=3 systemback-sustart

Here's the error message:

update-initramfs: Generating /boot/initrd.img-4.15.0-46-generic
W: Possible missing firmware /lib/firmware/i915/kbl_guc_ver9_14.bin for module i915
W: Possible missing firmware /lib/firmware/i915/bxt_guc_ver8_7.bin for module i915

 An error occurred while creating the following hard link:

  /home/.sbuserdata/home/jc/.mozilla/firefox

 Reference file:

  /home/jc/.mozilla/firefox

 /home/jc/.mozilla/firefox
  d rwx------ - 1000 1000 66313 -
 /home/jc/.mozilla
  d rwx------ - 1000 1000 66313 -
 /home/jc
  d rwxr-xr-x - 1000 1000 66313 -
 /home
  d rwxr-xr-x - 0 0 66313 -

 /home/.sbuserdata/home/jc/.mozilla/firefox
  -
 /home/.sbuserdata/home/jc/.mozilla
  d rwxr-xr-x - 0 0 66313 -
 /home/.sbuserdata/home/jc
  d rwxr-xr-x - 0 0 66313 -
 /home/.sbuserdata/home
  d rwxr-xr-x - 0 0 66313 -
 /home/.sbuserdata
  d rwxr-xr-x - 0 0 66313 -
 /home
  d rwxr-xr-x - 0 0 66313 -

 Errno: 1