I just did a fresh stock install (git clone https://github.com/odoo/odoo --branch 10.0 --depth 1 .) of Odoo 10.0 so I can evaluate it.  The first app I tried to install was Sales.  After pressing the 'install' button, I got the following error:

Traceback (most recent call last):
  File "/opt/odoo10-live/odoo/http.py", line 638, in _handle_exception
    return super(JsonRequest, self)._handle_exception(exception)
  File "/opt/odoo10-live/odoo/http.py", line 675, in dispatch
    result = self._call_function(**self.params)
  File "/opt/odoo10-live/odoo/http.py", line 331, in _call_function
    return checked_call(self.db, *args, **kwargs)
  File "/opt/odoo10-live/odoo/service/model.py", line 119, in wrapper
    return f(dbname, *args, **kwargs)
  File "/opt/odoo10-live/odoo/http.py", line 324, in checked_call
    result = self.endpoint(*a, **kw)
  File "/opt/odoo10-live/odoo/http.py", line 933, in __call__
    return self.method(*args, **kw)
  File "/opt/odoo10-live/odoo/http.py", line 504, in response_wrap
    response = f(*args, **kw)
  File "/opt/odoo10-live/addons/web/controllers/main.py", line 889, in call_button
    action = self._call_kw(model, method, args, {})
  File "/opt/odoo10-live/addons/web/controllers/main.py", line 877, in _call_kw
    return call_kw(request.env[model], method, args, kwargs)
  File "/opt/odoo10-live/odoo/api.py", line 681, in call_kw
    return call_kw_multi(method, model, args, kwargs)
  File "/opt/odoo10-live/odoo/api.py", line 672, in call_kw_multi
    result = method(recs, *args, **kwargs)
  File "/opt/odoo10-live/odoo/addons/base/module/module.py", line 410, in button_immediate_install
    return self._button_immediate_function(type(self).button_install)
  File "/opt/odoo10-live/odoo/addons/base/module/module.py", line 484, in _button_immediate_function
    modules.registry.Registry.new(self._cr.dbname, update_module=True)
  File "/opt/odoo10-live/odoo/modules/registry.py", line 82, in new
    odoo.modules.load_modules(registry._db, force_demo, status, update_module)
  File "/opt/odoo10-live/odoo/modules/loading.py", line 339, in load_modules
    loaded_modules, update_module)
  File "/opt/odoo10-live/odoo/modules/loading.py", line 237, in load_marked_modules
    loaded, processed = load_module_graph(cr, graph, progressdict, report=report, skip_modules=loaded_modules, perform_checks=perform_checks)
  File "/opt/odoo10-live/odoo/modules/loading.py", line 159, in load_module_graph
    _load_data(cr, module_name, idref, mode, kind='demo')
  File "/opt/odoo10-live/odoo/modules/loading.py", line 95, in _load_data
    tools.convert_file(cr, module_name, filename, idref, mode, noupdate, kind, report)
  File "/opt/odoo10-live/odoo/tools/convert.py", line 845, in convert_file
    convert_xml_import(cr, module, fp, idref, mode, noupdate, report)
  File "/opt/odoo10-live/odoo/tools/convert.py", line 915, in convert_xml_import
    obj.parse(doc.getroot(), mode=mode)
  File "/opt/odoo10-live/odoo/tools/convert.py", line 799, in parse
    self._tags[rec.tag](rec, de, mode=mode)
  File "/opt/odoo10-live/odoo/tools/convert.py", line 695, in _tag_record
    f_val = self.id_get(f_ref)
  File "/opt/odoo10-live/odoo/tools/convert.py", line 782, in id_get
    res = self.model_id_get(id_str, raise_if_not_found)
  File "/opt/odoo10-live/odoo/tools/convert.py", line 788, in model_id_get
    return self.env['ir.model.data'].xmlid_to_res_model_res_id(id_str, raise_if_not_found=raise_if_not_found)
  File "/opt/odoo10-live/odoo/addons/base/ir/ir_model.py", line 1075, in xmlid_to_res_model_res_id
    return self.xmlid_lookup(xmlid)[1:3]
  File "<string>", line 2, in xmlid_lookup
  File "/opt/odoo10-live/odoo/tools/cache.py", line 87, in lookup
    value = d[key] = self.method(*args, **kwargs)
  File "/opt/odoo10-live/odoo/addons/base/ir/ir_model.py", line 1064, in xmlid_lookup
    raise ValueError('External ID not found in the system: %s' % xmlid)
ParseError: "External ID not found in the system: base.user_demo" while parsing /opt/odoo10-live/addons/resource/data/resource_demo.xml:90, near
<record id="resource_designer" model="resource.resource">
            <field eval="100" name="time_efficiency"/>
            <field name="user_id" ref="base.user_demo"/>
            <field name="name">Designer</field>
            <field eval="1" name="active"/>
            <field name="calendar_id" ref="timesheet_group1"/>
            <field name="resource_type">user</field>
        </record>