HI,

Upgrade the module(s) that created the deleted groups in the first place.

I think "name" field is mandatory field,Kindly check before you save.

This is the error i get

OpenERP Server Error

Client Traceback (most recent call last): File "/opt/openerp/server/openerp/addons/web/http.py", line 204, in dispatch response["result"] = method(self, **self.params) File "/opt/openerp/server/openerp/addons/web/controllers/main.py", line 1132, in call_button action = self._call_kw(req, model, method, args, {}) File "/opt/openerp/server/openerp/addons/web/controllers/main.py", line 1120, in _call_kw return getattr(req.session.model(model), method)(*args, **kwargs) File "/opt/openerp/server/openerp/addons/web/session.py", line 42, in proxy result = self.proxy.execute_kw(self.session._db, self.session._uid, self.session._password, self.model, method, args, kw) File "/opt/openerp/server/openerp/addons/web/session.py", line 30, in proxy_method result = self.session.send(self.service_name, method, *args) File "/opt/openerp/server/openerp/addons/web/session.py", line 103, in send raise xmlrpclib.Fault(openerp.tools.ustr(e), formatted_info) Server Traceback (most recent call last): File "/opt/openerp/server/openerp/addons/web/session.py", line 89, in send return openerp.netsvc.dispatch_rpc(service_name, method, args) File "/opt/openerp/server/openerp/netsvc.py", line 296, in dispatch_rpc result = ExportService.getService(service_name).dispatch(method, params) File "/opt/openerp/server/openerp/service/web_services.py", line 626, in dispatch res = fn(db, uid, *params) File "/opt/openerp/server/openerp/osv/osv.py", line 190, in execute_kw return self.execute(db, uid, obj, method, *args, **kw or {}) File "/opt/openerp/server/openerp/osv/osv.py", line 150, in wrapper osv_pool = pooler.get_pool(dbname) File "/opt/openerp/server/openerp/pooler.py", line 49, in get_pool return get_db_and_pool(db_name, force_demo, status, update_module)[1] File "/opt/openerp/server/openerp/pooler.py", line 33, in get_db_and_pool registry = RegistryManager.get(db_name, force_demo, status, update_module) File "/opt/openerp/server/openerp/modules/registry.py", line 203, in get update_module) File "/opt/openerp/server/openerp/modules/registry.py", line 233, in new openerp.modules.load_modules(registry.db, force_demo, status, update_module) File "/opt/openerp/server/openerp/modules/loading.py", line 350, in load_modules force, status, report, loaded_modules, update_module) File "/opt/openerp/server/openerp/modules/loading.py", line 256, in load_marked_modules loaded, processed = load_module_graph(cr, graph, progressdict, report=report, skip_modules=loaded_modules, perform_checks=perform_checks) File "/opt/openerp/server/openerp/modules/loading.py", line 188, in load_module_graph load_data(module_name, idref, mode) File "/opt/openerp/server/openerp/modules/loading.py", line 76, in <lambda> load_data = lambda *args: _load_data(cr, *args, kind='data') File "/opt/openerp/server/openerp/modules/loading.py", line 124, in _load_data tools.convert_xml_import(cr, module_name, fp, idref, mode, noupdate, report) File "/opt/openerp/server/openerp/tools/convert.py", line 959, in convert_xml_import obj.parse(doc.getroot()) File "/opt/openerp/server/openerp/tools/convert.py", line 852, in parse self._tags[rec.tag](self.cr, rec, n) File "/opt/openerp/server/openerp/tools/convert.py", line 819, in _tag_record id = self.pool.get('ir.model.data')._update(cr, self.uid, rec_model, self.module, res, rec_id or False, not self.isnoupdate(data_node), noupdate=self.isnoupdate(data_node), mode=self.mode, context=rec_context ) File "/opt/openerp/server/openerp/addons/base/ir/ir_model.py", line 971, in _update res_id = model_obj.create(cr, uid, values, context=context) File "/opt/openerp/server/openerp/addons/base/res/res_users.py", line 685, in create res = super(groups_view, self).create(cr, uid, values, context) File "/opt/openerp/server/openerp/addons/base/res/res_users.py", line 598, in create gid = super(groups_implied, self).create(cr, uid, values, context) File "/opt/openerp/server/openerp/osv/orm.py", line 4515, in create cr.execute('insert into "'+self._table+'" (id'+upd0+") values ("+str(id_new)+upd1+')', tuple(upd2)) File "/opt/openerp/server/openerp/sql_db.py", line 161, in wrapper return f(self, *args, **kwargs) File "/opt/openerp/server/openerp/sql_db.py", line 226, in execute res = self._obj.execute(query, params) IntegrityError: null value in column "name" violates not-null constraint DETAIL: Failing row contains (135, null, 1, 2014-08-01 19:11:52.871901, 2014-08-01 19:11:52.871901, 1, null, null, f, f).