Hello,
I have installed CODE on one server and Nextcloud on another, and each time I open a document in Collabora, I got a
WRN chmod("/opt/cool/child-roots/XXXXX/YYYYYY/lo/") failed: Read-only file system| common/JailUtil.cpp:282
I have try to chmod 777 and chown cool:cool on /opt/cool without success.
Where come from this log and what can I do to solve this error ? 
Hey @shadow.gfa,
Welcome to the forum + thanks for the question.
Which versions of CODE + Nextcloud are you using?
Can you please go into the Collabora’s Help > About and post the exact info too?
Hmmm… and is everything working fine?
I think I recall that specific JailUtil.cpp WRN/Warning being not that important now, but I may be completely misremembering.
I think it’s just a temp file/folder where Collabora tosses “temp copies of the opened documents so they can’t escape”.
(I recall issues with users not being able to SAVE files, but I think those issues got squished. [I think in that case, you’d see `ERR` instead.])
And if yours is running fine, I don’t believe you have to worry about this in the log.
The warning is bogus; @ash patched it out in more recent builds - thanks for reporting: did that get back-ported to 23.05 Ash ?