vba - How Can You Delete All Color Categories?

I'm trying to delete all the color categories. However, the following code doesn't always delete all cases, typically leaving two or three.

Any reason it'd skip some categories?

    Public Sub DeleteAllCategories()
        On Error GoTo MyErrorHandler

        'Assume gOutlookApp (as in Dim gOutlookApp As Outlook.Application) is valid
        Dim theCategories As Outlook.Categories
        Set theCategories = gOutlookApp.Session.Categories


        Dim i As Long
        For i = 1 To theCategories.Count
            theCategories.Remove 1
            DoEvents
        Next

        Exit Sub

    MyErrorHandler:

        MsgBox "DeleteAllCategories" & vbCrLf & vbCrLf & "Err = " & Err.Number & vbCrLf & "Description: " & Err.Description
    End Sub