Upgrade failed - Plone 4.3.7 to Plone 5.0

Question

I'm trying to upgrade Plone 4.3.7 to Plone 5.0 via the portal_migration tool, and encounter the following error. Any thoughts? This is simple site (no add-ons), but it dates back to Plone 2.x, so there may be some old crud left that I've forgotten about.

Output of UPGRADE tool:

Dry run selected.
Starting the migration from version: 4311
Ran upgrade step: Miscellaneous
Role / permission map imported.
Archetype tool imported.
Step languagetool has an invalid import handler
Step kupu-setup 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
Ran upgrade step: Upgrade site control panel settings
Role / permission map imported.
Skins tool imported.
Archetype tool imported.
Step languagetool has an invalid import handler
Step kupu-setup has an invalid import handler
Ran upgrade step: Run to50beta1 upgrade profile
Ran upgrade step: Upgrade markup control panel settings
Ran upgrade step: Upgrade mail control panel settings
Ran upgrade step: Upgrade security control panel settings
Upgrade aborted. Error:
Traceback (most recent call last):
  File "/usr/local/Plone/buildout-cache/eggs/Products.CMFPlone-5.0-py2.7.egg/Products/CMFPlone/MigrationTool.py", line 257, in upgrade
    step['step'].doStep(setup)
  File "/usr/local/Plone/buildout-cache/eggs/Products.GenericSetup-1.8.0-py2.7.egg/Products/GenericSetup/upgrade.py", line 166, in doStep
    self.handler(tool)
  File "/usr/local/Plone/buildout-cache/eggs/plone.app.upgrade-1.3.18-py2.7.egg/plone/app/upgrade/v50/betas.py", line 63, in upgrade_portal_language
    lang_settings.use_content_negotiation = portal_languages.use_content_negotiation
AttributeError: use_content_negotiation
Starting upgrade of core addons.
Done upgrading core addons.
End of upgrade path, migration has finished
The upgrade path did NOT reach current version
Migration has failed
Dry run selected, transaction aborted

If I just try to view the site itself, I see a blank page with this error message:

    KeyError('Interface `Products.CMFPlone.interfaces.controlpanel.ILanguageSchema` 
defines a field `available_languages`, for which there is no record.',)
 (Also, the following error occurred while attempting to render the 
standard error message, please see the event log for full details: 
Interface `Products.CMFPlone.interfaces.controlpanel.ILanguageSchema`
 defines a field `available_languages`, for which there is no record.)

At the debug mode console, I see repeated error messages like this:

2015-10-09 13:52:28 INFO plone.app.upgrade Dry run selected.
2015-10-09 13:52:28 INFO plone.app.upgrade Starting the migration from version: 4311
2015-10-09 13:52:28 INFO plone.app.upgrade Ran upgrade step: Miscellaneous
2015-10-09 13:52:28 INFO Products.GenericSetup.tool Importing profile profile-plone.app.upgrade.v50:to50alpha3 with dependency strategy upgrade.
2015-10-09 13:52:28 INFO Products.GenericSetup.tool Applying main profile profile-plone.app.upgrade.v50:to50alpha3
2015-10-09 13:52:29 INFO GenericSetup.rolemap Role / permission map imported.
/usr/local/Plone/buildout-cache/eggs/Products.CMFCore-2.2.10-py2.7.egg/Products/CMFCore/DirectoryView.py:493: UserWarning: DirectoryView plone_deprecated refers to a non-existing path 'Products.CMFPlone:skins/plone_deprecated'
  (self.id, reg_key), UserWarning)
/usr/local/Plone/buildout-cache/eggs/Products.CMFCore-2.2.10-py2.7.egg/Products/CMFCore/DirectoryView.py:493: UserWarning: DirectoryView plone_styles refers to a non-existing path 'Products.CMFPlone:skins/plone_styles'
  (self.id, reg_key), UserWarning)
/usr/local/Plone/buildout-cache/eggs/Products.CMFCore-2.2.10-py2.7.egg/Products/CMFCore/DirectoryView.py:493: UserWarning: DirectoryView classic_ecmascript refers to a non-existing path 'plonetheme.classic:skins/classic_ecmascript'
  (self.id, reg_key), UserWarning)
2015-10-09 13:52:29 INFO GenericSetup.archetypetool Archetype tool imported.
2015-10-09 13:52:29 ERROR GenericSetup Step languagetool has an invalid import handler
2015-10-09 13:52:29 ERROR GenericSetup Step kupu-setup has an invalid import handler
2015-10-09 13:52:29 INFO plone.app.upgrade Ran upgrade step: Run to50alpha3 upgrade profile
2015-10-09 13:52:29 INFO plone.app.upgrade Ran upgrade step: Upgrade editing control panel settings
2015-10-09 13:52:29 INFO plone.app.upgrade Ran upgrade step: Upgrade maintenance control panel settings
2015-10-09 13:52:29 INFO plone.app.upgrade Ran upgrade step: Upgrade navigation control panel settings
2015-10-09 13:52:29 INFO plone.app.upgrade Ran upgrade step: Upgrade search control panel settings
2015-10-09 13:52:29 INFO plone.app.upgrade Ran upgrade step: Upgrade site control panel settings
2015-10-09 13:52:29 INFO Products.GenericSetup.tool Importing profile profile-plone.app.upgrade.v50:to50beta1 with dependency strategy upgrade.
2015-10-09 13:52:29 INFO Products.GenericSetup.tool Applying main profile profile-plone.app.upgrade.v50:to50beta1
2015-10-09 13:52:29 INFO GenericSetup.rolemap Role / permission map imported.
2015-10-09 13:52:29 INFO GenericSetup.skins Skins tool imported.
2015-10-09 13:52:29 INFO GenericSetup.archetypetool Archetype tool imported.
2015-10-09 13:52:29 ERROR GenericSetup Step languagetool has an invalid import handler
2015-10-09 13:52:29 ERROR GenericSetup Step kupu-setup has an invalid import handler
2015-10-09 13:52:29 INFO plone.app.upgrade Ran upgrade step: Run to50beta1 upgrade profile
2015-10-09 13:52:29 ERROR PortalTransforms Cannot register transform html-to-captioned (ImportError), using BrokenTransform: Error
 No module named html2captioned
2015-10-09 13:52:29 INFO plone.app.upgrade Ran upgrade step: Upgrade markup control panel settings
2015-10-09 13:52:29 INFO plone.app.upgrade Ran upgrade step: Upgrade mail control panel settings
2015-10-09 13:52:29 INFO plone.app.upgrade Ran upgrade step: Upgrade security control panel settings
2015-10-09 13:52:29 ERROR plone.app.upgrade Upgrade aborted. Error:
Traceback (most recent call last):
  File "/usr/local/Plone/buildout-cache/eggs/Products.CMFPlone-5.0-py2.7.egg/Products/CMFPlone/MigrationTool.py", line 257, in upgrade
    step['step'].doStep(setup)
  File "/usr/local/Plone/buildout-cache/eggs/Products.GenericSetup-1.8.0-py2.7.egg/Products/GenericSetup/upgrade.py", line 166, in doStep
    self.handler(tool)
  File "/usr/local/Plone/buildout-cache/eggs/plone.app.upgrade-1.3.18-py2.7.egg/plone/app/upgrade/v50/betas.py", line 63, in upgrade_portal_language
    lang_settings.use_content_negotiation = portal_languages.use_content_negotiation
AttributeError: use_content_negotiation
2015-10-09 13:52:29 INFO plone.app.upgrade Starting upgrade of core addons.
2015-10-09 13:52:29 INFO Products.GenericSetup.tool No upgrades available for profile Products.CMFEditions:CMFEditions. Profile stays at version ('4',).
2015-10-09 13:52:29 WARNING Products.GenericSetup.tool Version of profile Products.CMFPlacefulWorkflow:CMFPlacefulWorkflow is unknown, refusing to upgrade.
2015-10-09 13:52:29 WARNING Products.GenericSetup.tool Version of profile plone.app.contenttypes:default is unknown, refusing to upgrade.
2015-10-09 13:52:29 WARNING Products.GenericSetup.tool Version of profile plone.app.dexterity:default is unknown, refusing to upgrade.
2015-10-09 13:52:29 INFO Products.GenericSetup.tool No upgrades available for profile plone.app.discussion:default. Profile stays at version ('102',).
2015-10-09 13:52:29 WARNING Products.GenericSetup.tool Version of profile plone.app.event:default is unknown, refusing to upgrade.
2015-10-09 13:52:29 WARNING Products.GenericSetup.tool Version of profile plone.app.iterate:plone.app.iterate is unknown, refusing to upgrade.
2015-10-09 13:52:29 WARNING Products.GenericSetup.tool Version of profile plone.app.multilingual:default is unknown, refusing to upgrade.
2015-10-09 13:52:29 INFO Products.GenericSetup.tool No upgrades available for profile plone.app.querystring:default. Profile stays at version ('11',).
2015-10-09 13:52:29 WARNING Products.GenericSetup.tool Version of profile plone.app.theming:default is unknown, refusing to upgrade.
2015-10-09 13:52:29 WARNING Products.GenericSetup.tool Version of profile plone.app.users:default is unknown, refusing to upgrade.
2015-10-09 13:52:29 INFO plone.app.upgrade Done upgrading core addons.
2015-10-09 13:52:29 INFO plone.app.upgrade End of upgrade path, migration has finished
2015-10-09 13:52:29 ERROR plone.app.upgrade The upgrade path did NOT reach current version
2015-10-09 13:52:29 ERROR plone.app.upgrade Migration has failed
2015-10-09 13:52:29 INFO plone.app.upgrade Dry run selected, transaction aborted

Answer 1

Are there any 3rd-party products installed? Maybe LinguaPlone? The important part here is AttributeError: use_content_negotiation, so it seems your migration is stuck somewhere into Products.PloneLanguageTool.

You may try "updating" your portal_languages object in ZMI from a new Plone site created in the same instance. Or uninstalling LinguaPlone before migration if that is possible (ie: there isn't too much content using it).