first if the excel extension is xls then convert it using excel to xlsx .then close excel. make a backup of your xlsx file. rename this backup extension to zip. under zip file there is a xl folder.under the xl folder there is a workbook.xml file. open it with xml notepad and delete defined names. or open it with notepad delete between <definednames> to </definednames>. and also delete this definednames parts too.then save this workbook.xml and drag drop inside zip files xl folder . then save it. and change the extension to xlsx file. open the file and press Ctrl+S. All defined names cleared with hidden ones.

You should check if it is an internal protected name range like so
```
Sub DeleteNames()
Dim xName As Name
For Each xName In Application.ActiveWorkbook.Names
If Split(xName.Name, ".")(0) <> "_xlfn" Then
xName.Delete
End If
Next
End Sub
```

Run Time Error 7
out of memory

How about something a little more specific.

First Identify all unused named ranges, for review.

Second, macro to delete all unused named ranges.

When I try to run the above VBA Code, I get the following error:

Run-time error '1004'
The syntax of this name isn't correct.

Verify that the name:
- Starts with a letter or underscore
- Doesn't include a space or character that isn't allowed
- Doesn't conflict with an existing name in the workbook