UnicodeDecodeError on save

[cyberdoud]

After editing a page, an error message pops up on save (I've copied the content below).
Some extra information (usually hidden) has appeared on top of the page :

Content-Type: text/x-zim-wiki
Wiki-Format: zim 0.4
Creation-Date: 2016-09-29T08:57:16+02:00

I've deleted these lines and I've been able to save the page without errors.

Extra information: My notes are saved in a Cryptomator volume.

Error log:

This is zim 0.65
Platform: nt
Locale: fr_FR cp1252
FS encoding: mbcs
Python: (2, 7, 11, 'final', 0)
Gtk: (2, 24, 10)
Pygtk: (2, 24, 0)
Zim revision is:
  branch: 065
  revision: 805 <email address hidden>
  date: 2015-11-01 15:42:45 +0100

======= Traceback =======
  File "zim\gui\__init__.pyo", line 885, in _action_handler
  File "zim\gui\__init__.pyo", line 1558, in save_page
  File "zim\gui\__init__.pyo", line 1579, in _save_page
  File "zim\gui\__init__.pyo", line 3116, in __init__
UnicodeDecodeError: 'utf8' codec can't decode byte 0xe9 in position 28: invalid continuation byte

[Launchpad Janitor (janitor)]

[Expired for Zim because there has been no activity for 60 days.]