[DiapDealer]

Originally Posted by duns

Maybe I have too many Python on my kubuntu?

It's possible I guess. I certainly don't think python 3.7 is standard on 17.10. You may not have a stable python3 environment at this point.

In any case, you need to verify that lxml is working properly outside of Sigil. Until it does, we probably can't be much help. From a terminal, you should be able to start an interactive python shell with:

python3

Verify which version of python is being used and then use:
(pressing enter after each command)

import sys

from lxml import etree

and see if the import is successful.

Then print your sys.path and report back the results

print(sys.path)

Exit the interactive python shell with:

exit()