Power BI Desktop Copy or Duplicate Object now fails

[Michaeldias]

For a specific model I now get the following errors every time I try to copy or duplicate an object.
Has anyone seen this or know if a fix is in the pipeline?

I don't wish anyone to continue with this kind of error making them worry about a corrupted model that wont open at some point.  So I'll go back 2 days and redo 8 hours of work and hope it does not reappear.

Duplicate

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Feedback Type:
Frown (Error)

Timestamp:
2025-08-15T10:40:40.5217097Z

Local Time:
2025-08-15T11:40:40.5217097+01:00

Session ID:
4df21d65-7052-454f-813a-c286dfb55e14

Release:
August 2025

Product Version:
2.146.705.0 (25.08)+b71502aff0a01340c88f384884ef42771068f115 (x64)

Error Message:
Item has already been added. Key in dictionary: 'Interface_Change_Log' Key being added: 'Interface_Change_Log'

Stack Trace:
System.ArgumentException
at System.Collections.Hashtable.Insert(Object key, Object nvalue, Boolean add)
at System.Collections.Specialized.OrderedDictionary.Add(Object key, Object value)
at Microsoft.Mashup.Host.Document.Model.Queries.OnQueriesAdded(Query[] queriesAdded)
at Microsoft.Mashup.Host.Document.Model.Query.NotifyDuplicated(Query newQuery)
at Microsoft.Mashup.Host.Document.Model.Query.<>c__DisplayClass253_0.<Duplicate>b__1(PackageEditor packageEditor)
at Microsoft.Mashup.Host.Document.Model.Queries.InvokeWithPackageEditor[T](Nullable`1 changeReason, Func`2 action)
at Microsoft.Mashup.Host.Document.Model.Query.Duplicate(Boolean makePrivate)
at Microsoft.Mashup.Client.UI.Shared.QueryServices.TryDuplicateQuery(Query query, Query& duplicatedQuery)
at Microsoft.Mashup.Client.UI.Shared.HtmlControls.BaseQueriesNavigatorHtmlControl.OnDuplicateContextMenuButtonClick(Query query)
at Microsoft.Mashup.Client.UI.Windows.ContextMenuRenderer.<>c__DisplayClass22_0.<CreateMenuItem>b__1()
at Microsoft.Mashup.Host.Document.ExceptionHandlerExtensions.HandleExceptions(IExceptionHandler exceptionHandler, Action action)

Stack Trace Message:
Item has already been added. Key in dictionary: 'Interface_Change_Log' Key being added: 'Interface_Change_Log'

Invocation Stack Trace:
at Microsoft.Mashup.Host.Document.ExceptionExtensions.GetCurrentInvocationStackTrace()
at Microsoft.Mashup.Client.UI.Shared.StackTraceInfo..ctor(String exceptionStackTrace, String invocationStackTrace, String exceptionMessage)
at Microsoft.PowerBI.Client.Windows.Telemetry.PowerBIUserFeedbackServices.GetStackTraceInfo(Exception e)
at Microsoft.PowerBI.Client.Windows.Telemetry.PowerBIUserFeedbackServices.ReportException(IWindowHandle activeWindow, IUIHost uiHost, FeedbackPackageInfo feedbackPackageInfo, Exception e, Boolean useGDICapture)
at Microsoft.Mashup.Client.UI.Shared.UnexpectedExceptionHandler.<>c__DisplayClass14_0.<HandleException>b__0()
at Microsoft.Mashup.Client.UI.Shared.UnexpectedExceptionHandler.HandleException(Exception e)
at Microsoft.Mashup.Host.Document.ExceptionHandlerExtensions.HandleExceptions(IExceptionHandler exceptionHandler, Action action)
at System.Windows.Forms.ToolStripItem.RaiseEvent(Object key, EventArgs e)
at System.Windows.Forms.ToolStripMenuItem.OnClick(EventArgs e)
at System.Windows.Forms.ToolStripItem.HandleClick(EventArgs e)
at System.Windows.Forms.ToolStripItem.HandleMouseUp(MouseEventArgs e)
at System.Windows.Forms.ToolStrip.OnMouseUp(MouseEventArgs mea)
at System.Windows.Forms.ToolStripDropDown.OnMouseUp(MouseEventArgs mea)
at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.ToolStrip.WndProc(Message& m)
at System.Windows.Forms.ToolStripDropDown.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)
at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)
at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(IntPtr 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.Form.ShowDialog(IWin32Window owner)
at Microsoft.Mashup.Client.UI.Shared.WindowManager.ShowModal[T](T dialog, Func`1 showModalFunction)
at Microsoft.PowerBI.Client.AppModule.<>c__DisplayClass3_0.<Run>b__0()
at Microsoft.PowerBI.Client.Windows.IExceptionHandlerExtensions.<>c__DisplayClass3_0.<HandleExceptionsWithNestedTasks>b__0()
at Microsoft.Mashup.Host.Document.ExceptionHandlerExtensions.HandleExceptions(IExceptionHandler exceptionHandler, Action action)
at Microsoft.PowerBI.Client.AppModule.Run()
at Microsoft.PowerBI.Client.Program.RunApplicationFlow(String[] args, IPowerBIRootTrace trace)
at Microsoft.PowerBI.Client.Program.Main(String[] args)

PowerBINonFatalError:
{"AppName":"PBIDesktop","AppVersion":"2.146.705.0","ModuleName":"Microsoft.Mashup.Document.dll","Component":"Microsoft.Mashup.Host.Document.Model.Queries","Error":"System.ArgumentException","MethodDef":"OnQueriesAdded","ErrorOffset":"41","ErrorCode":""}

WebView2 Runtime Version:
139.0.3405.86

WebView2 SDK Version:
1.0.2365.46

Copy

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Error Message:
An item with the same key has already been added.

Stack Trace Message:
An item with the same key has already been added.

PowerBINonFatalError:
{"AppName":"PBIDesktop","AppVersion":"2.146.705.0","ModuleName":"Microsoft.MashupEngine.dll","Component":"Microsoft.Mashup.Evaluator.MemberLetPartitionedDocument+ReferenceVisitor","Error":"System.ArgumentException","MethodDef":".ctor","ErrorOffset":"173","ErrorCode":""}

[Michaeldias · Accepted solution]

A 'fix' for this was to Export the template.  Save As .pbit file.

Then open a new dataset in Power BI and import model from the template.

New model exhibits no problems now.

Please also backup often as some forms of corrupted pbix files will not even open once Desktop is closed.

Feel free to accept it this works for you

[wardy912]

Hi @Michaeldias 

 This is AI generated and unvalidated but I hope it helps:

 Issue Summary

You're encountering a System.ArgumentException in Power BI Desktop (version 2.146.705.0, August 2025 release) when attempting to duplicate a query. The error message:

"Item has already been added. Key in dictionary: 'Interface_Change_Log'"

...indicates that Power BI is trying to add a query with a name that already exists in the internal dictionary, causing a conflict.

---

🧩 Known Issue

This is a known issue affecting multiple users, especially when duplicating queries or working with models that have previously been saved with certain naming conventions . It can lead to corrupted PBIX files that fail to open later.

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✅ Workarounds

Until Microsoft releases a fix, here are some recommended workarounds:

1. Avoid using the Duplicate option directly:

   • Instead, create a blank query and manually copy the M code from the original query using the Advanced Editor .

2. Check for duplicate query names:

   • Even if names look unique, Power BI may treat them as duplicates due to internal metadata conflicts. Renaming queries before duplication might help.

3. Use version control manually:

   • Save incremental versions of your PBIX file (e.g., Model_v1.pbix, Model_v2.pbix) to avoid losing hours of work if corruption occurs.

4. Avoid syncing with OneDrive or cloud folders during development:

   • Some users reported fewer issues when working locally rather than in synced folders .

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🛠️ Fix Status

As of now, no official fix has been listed in the Power BI Desktop change log 

 or the Known Issues page 

 for the August 2025 release. However, Microsoft is aware of similar issues and has addressed related bugs in previous updates.

[Michaeldias]

Thanks Wardy.

1. will only take me so far I think.  I started to get other strange errors appear such as visuals showing errors.
3. Yep - always... but not as often as I like and it's hard to know which version has what and which version is showing issues.

4. One Drive - definitely.  Seen this with Excel files which Power Query.  For these I use VBA to save and export VBA modules and Power Query items. The only thing I lose is folders.  I can import back too... which brings me full circle to my next answer