Plone5をアップグレードしようとしたらエラーになってしまった．

Dry run selected.
Starting the migration from version: 5001
Role / permission map imported.
Step languagetool has an invalid import handler
Ran upgrade step: Run to50alpha3 upgrade profile
Ran upgrade step: Upgrade editing control panel settings
Ran upgrade step: Upgrade maintenance control panel settings
Ran upgrade step: Upgrade navigation control panel settings
Ran upgrade step: Upgrade search control panel settings
Upgrade aborted. Error:
Traceback (most recent call last):
  File "buildout.coredev/src/Products.CMFPlone/Products/CMFPlone/MigrationTool.py", line 268, in upgrade
    step['step'].doStep(setup)
  File "buildout.coredev/src/Products.GenericSetup/Products/GenericSetup/upgrade.py", line 166, in doStep
    self.handler(tool)
  File "buildout.coredev/src/plone.app.upgrade/plone/app/upgrade/v50/alphas.py", line 312, in upgrade_site_controlpanel_settings
    settings.site_title = unicode(portal.title)
UnicodeDecodeError: 'ascii' codec can't decode byte 0xe3 in position 0: ordinal not in range(128)
End of upgrade path, main migration has finished.
The upgrade path did NOT reach current version.
Migration has failed
Dry run selected, transaction aborted

やってしまった．．．　

 ____________________ 
< UnicodeDecodeError >
 -------------------- 
        \   ^__^
         \  (oo)\_______
            (__)\       )\/\
                ||----w |
                ||     ||

である．

この手のエラーは， site-packages に sitecustomize.py を設置することで対処でき，以下のように記述する．

import sys
sys.setdefaultencoding("utf-8")

Plone 5を再起動する．

再度アップグレードにチャレンジ．

アップグレードできた！

Your Plone instance is now up-to-date.