We have this exception

SD.LLBLGen.Pro.ORMSupportClasses.ORMRelationException was unhandled Message="Relation at index 5 doesn't contain an entity already added to the FROM clause. Bad alias?" Source="SD.LLBLGen.Pro.ORMSupportClasses.NET20" RuntimeBuild="10122008" RuntimeVersion="2.5.0.0" StackTrace: at SD.LLBLGen.Pro.ORMSupportClasses.RelationCollection.ToQueryText(Int32& uniqueMarker) at SD.LLBLGen.Pro.DQE.SqlServer.DynamicQueryEngine.CreateSelectDQ(IEntityFieldCore[] selectList, IFieldPersistenceInfo[] fieldsPersistenceInfo, IDbConnection connectionToUse, IPredicate selectFilter, Int64 maxNumberOfItemsToReturn, ISortExpression sortClauses, IRelationCollection relationsToWalk, Boolean allowDuplicates, IGroupByCollection groupByClause, Boolean relationsSpecified, Boolean sortClausesSpecified) at SD.LLBLGen.Pro.ORMSupportClasses.DynamicQueryEngineBase.CreateSelectDQ(IEntityFieldCore[] selectList, IFieldPersistenceInfo[] fieldsPersistenceInfo, IDbConnection connectionToUse, IPredicate selectFilter, Int64 maxNumberOfItemsToReturn, ISortExpression sortClauses, IRelationCollection relationsToWalk, Boolean allowDuplicates, IGroupByCollection groupByClause) at SD.LLBLGen.Pro.DQE.SqlServer.DynamicQueryEngine.CreatePagingSelectDQ(IEntityFieldCore[] selectList, IFieldPersistenceInfo[] fieldsPersistenceInfo, IDbConnection connectionToUse, IPredicate selectFilter, Int64 maxNumberOfItemsToReturn, ISortExpression sortClauses, IRelationCollection relationsToWalk, Boolean allowDuplicates, IGroupByCollection groupByClause, Int32 pageNumber, Int32 pageSize) at SD.LLBLGen.Pro.ORMSupportClasses.DynamicQueryEngineBase.CreateSelectDQ(IEntityFieldCore[] selectList, IFieldPersistenceInfo[] fieldsPersistenceInfo, IDbConnection connectionToUse, IPredicate selectFilter, Int64 maxNumberOfItemsToReturn, ISortExpression sortClauses, IRelationCollection relationsToWalk, Boolean allowDuplicates, IGroupByCollection groupByClause, Int32 pageNumber, Int32 pageSize) at SD.LLBLGen.Pro.ORMSupportClasses.DataAccessAdapterBase.CreateSelectDQ(IEntityFields2 fieldsToFetch, IFieldPersistenceInfo[] persistenceInfoObjects, IPredicateExpression filter, Int64 maxNumberOfItemsToReturn, ISortExpression sortClauses, IRelationCollection relationsToWalk, Boolean allowDuplicates, IGroupByCollection groupByClause, Int32 pageNumber, Int32 pageSize) at SD.LLBLGen.Pro.ORMSupportClasses.DataAccessAdapterBase.CreateQueryFromElements(IEntityFields2 fieldCollectionToFetch, IRelationPredicateBucket filterBucket, Int32 maxNumberOfItemsToReturn, ISortExpression sortClauses, Boolean allowDuplicates, IGroupByCollection groupByClause, Int32 pageNumber, Int32 pageSize, IFieldPersistenceInfo[]& persistenceInfo, IRetrievalQuery& selectQuery) at SD.LLBLGen.Pro.ORMSupportClasses.DataAccessAdapterBase.FetchTypedList(IEntityFields2 fieldCollectionToFetch, DataTable dataTableToFill, IRelationPredicateBucket filterBucket, Int32 maxNumberOfItemsToReturn, ISortExpression sortClauses, Boolean allowDuplicates, IGroupByCollection groupByClause, Int32 pageNumber, Int32 pageSize) at SD.LLBLGen.Pro.ORMSupportClasses.DataAccessAdapterBase.FetchTypedList(ITypedListLgp2 typedListToFill, IPredicateExpression additionalFilter) at PumpBowler.Client.Library.DataAccess.ClientDataSource.GetHeadSelectionList(ExitSelectionQuery query) in D:\projects\pb\src\PumpBowler.Client.Library\DataAccess\ClientDataSource.cs:line 264 at PumpBowler.Client.Pc.Wizards.wzPumpSelection.CikisSecmeHazirlik() in D:\projects\pb\src\PumpBowler.Client.Pc\Wizards\wzPumpSelection.cs:line 1571 at PumpBowler.Client.Pc.Wizards.wzPumpSelection.CikisSecmeEvents() in D:\projects\pb\src\PumpBowler.Client.Pc\Wizards\wzPumpSelection.cs:line 1531 at PumpBowler.Client.Pc.Wizards.wzPumpSelection.LoadEvents(WizardSteps Step) in D:\projects\pb\src\PumpBowler.Client.Pc\Wizards\wzPumpSelection.cs:line 702 at PumpBowler.Client.Pc.Wizards.wzPumpSelection.sbNext_Click(Object sender, EventArgs e) in D:\projects\pb\src\PumpBowler.Client.Pc\Wizards\wzPumpSelection.cs:line 605 at System.Windows.Forms.Control.OnClick(EventArgs e) at DevExpress.XtraEditors.BaseButton.OnClick(EventArgs e) at DevExpress.XtraEditors.BaseButton.OnMouseUp(MouseEventArgs e) at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks) at System.Windows.Forms.Control.WndProc(Message& m) at DevExpress.Utils.Controls.ControlBase.WndProc(Message& m) at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m) at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m) at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam) at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg) at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(Int32 dwComponentID, Int32 reason, Int32 pvLoopData) at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context) at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context) at System.Windows.Forms.Application.RunDialog(Form form) at System.Windows.Forms.Form.ShowDialog(IWin32Window owner) at System.Windows.Forms.Form.ShowDialog() at PumpBowler.Client.Pc.frmxMain.CreateModalForm(XtraForm Form) in D:\projects\pb\src\PumpBowler.Client.Pc\frmxMain.cs:line 233 at PumpBowler.Client.Pc.frmxMain.bbiPSW_ItemClick(Object sender, ItemClickEventArgs e) in D:\projects\pb\src\PumpBowler.Client.Pc\frmxMain.cs:line 243 at DevExpress.XtraBars.BarItem.OnClick(BarItemLink link) at DevExpress.XtraBars.BarBaseButtonItem.OnClick(BarItemLink link) at DevExpress.XtraBars.BarItemLink.OnLinkClick() at DevExpress.XtraBars.BarItemLink.OnLinkAction(BarLinkAction action, Object actionArgs) at DevExpress.XtraBars.BarButtonItemLink.OnLinkAction(BarLinkAction action, Object actionArgs) at DevExpress.XtraBars.BarItemLink.OnLinkActionCore(BarLinkAction action, Object actionArgs) at DevExpress.XtraBars.ViewInfo.BarSelectionInfo.ClickLink(BarItemLink link) at DevExpress.XtraBars.ViewInfo.BarSelectionInfo.UnPressLink(BarItemLink link) at DevExpress.XtraBars.Controls.CustomLinksControl.OnMouseUp(MouseEventArgs e) at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks) at System.Windows.Forms.Control.WndProc(Message& m) at DevExpress.XtraBars.Controls.DockedBarControl.WndProc(Message& msg) at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m) at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m) at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam) at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg) at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(Int32 dwComponentID, Int32 reason, Int32 pvLoopData) at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context) at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context) at System.Windows.Forms.Application.Run(Form mainForm) at PumpBowler.Client.Pc.Program.Main() in D:\projects\pb\src\PumpBowler.Client.Pc\Program.cs:line 30 at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args) at System.AppDomain.nExecuteAssembly(Assembly assembly, String[] args) at System.Runtime.Hosting.ManifestRunner.Run(Boolean checkAptModel) at System.Runtime.Hosting.ManifestRunner.ExecuteAsAssembly() at System.Runtime.Hosting.ApplicationActivator.CreateInstance(ActivationContext activationContext, String[] activationCustomData) at System.Runtime.Hosting.ApplicationActivator.CreateInstance(ActivationContext activationContext) at System.Activator.CreateInstance(ActivationContext activationContext) at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssemblyDebugInZone() at System.Threading.ThreadHelper.ThreadStart_Context(Object state) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Threading.ThreadHelper.ThreadStart() InnerException:

Generated relations here:

/// <summary>Builds the relation set for this typed list, inside the filterBucket object.</summary>
        private void BuildRelationSet()
        {
            _filterBucket.Relations.ObeyWeakRelations = base.ObeyWeakRelations;
            _filterBucket.Relations.Add(HeadAssemblyStretchAssemblyEntity.Relations.StretchAssemblyEntityUsingFkStretchAssembly, "", "", JoinHint.None);
            _filterBucket.Relations.Add(HeadAssemblyEntity.Relations.HeadAssemblyStretchAssemblyEntityUsingFkHeadAssembly, "", "", JoinHint.Cross);
            _filterBucket.Relations.Add(HeadAssemblyEntity.Relations.HeadAssemblyGasketAssemblyEntityUsingFkHeadAssembly, "", "", JoinHint.Cross);
            _filterBucket.Relations.Add(HeadAssemblyGasketAssemblyEntity.Relations.GasketAssemblyEntityUsingFkGasketAssembly, "", "", JoinHint.None);
            _filterBucket.Relations.Add(HeadAssemblyEntity.Relations.PartEntityUsingFkHead, "", "Head", JoinHint.None);
            
            // __LLBLGENPRO_USER_CODE_REGION_START AdditionalRelations
            // __LLBLGENPRO_USER_CODE_REGION_END
            
            OnRelationSetBuilt(_filterBucket.Relations);
        }

We don't know why we are getting this exception...

Regards...

Please try this: change the second relation with this (switch them):

_filterBucket.Relations.Add(HeadAssemblyStretchAssemblyEntity.Relations.HeadAssemblyEntityUsingFkHeadAssembly, "", "", JoinHint.Cross);