Dconf error: "'/root/.cache/dconf': Permission denied"

NC 15.05 & Preview Generator 2.1.0 on Ubuntu 18.04

At the first run of occ preview:generate-all, i’ve got following error message a few times:

(process:3448): dconf-CRITICAL **: 15:13:42.566: unable to create directory '/root/.cache/dconf': Permission denied.  dconf will not work properly.
func=xmlSecCheckVersionExt:file=xmlsec.c:line=188:obj=unknown:subj=unknown:error=19:invalid version:mode=abi compatible;expected minor version=2;real minor version=2;expected subminor version=25;real subminor version=26

i have executed the occ command as root like this:

sudo -u www-run php occ preview:generate-all

What does that error message mean?

Is it the reason why previews for DOC, XLS, PDF, AVI and MP4 are not being generated?

I’ve filed a bug @rullzer

The answer is here @rullzer: https://github.com/rullzer/previewgenerator/issues/154#issuecomment-493752954