How do I change the color of Strikethrough without changing the color of the text?

The only way I can envisage that kind of behaviour occurring is if you have Track Changes 'on'; I am unable to reproduce it otherwise and the macro applies only a red strikethough to the selected text. That said, the quality of the strikethough varies somewhat with the font being used You might get a better result with:

Sub ColouredStrikethrough()

Application.ScreenUpdating = False

ActiveWindow.View.ShowFieldCodes = False

Dim SngWdth As Single, i As Long

Dim StrTxt As String, StrTmp As String

Dim Fld As Field, Rng As Range, SngPos As Single

With Selection.Range

  While .Characters.Last.Information(wdVerticalPositionRelativeToPage) <> _

    .Characters.First.Information(wdVerticalPositionRelativeToPage)

    .MoveEnd wdCharacter, -1

  Wend

  If .Characters.Last Like "[ " & Chr(160) & vbTab & "]" Then .End = .End - 1

  SngPos = .Characters.Last.Information(wdHorizontalPositionRelativeToPage)

  SngWdth = SngPos - .Characters.First.Previous.Information(wdHorizontalPositionRelativeToPage)

  If SngWdth = 0 Then Exit Sub

  Set Rng = .Duplicate

  Rng.Collapse wdCollapseEnd

  Set Fld = .Fields.Add(Range:=Rng, Type:=wdFieldEmpty, _

    PreserveFormatting:=False, Text:="ADVANCE \l " & Round(SngWdth, 1))

  With Rng

    .End = Fld.Result.End

    .Collapse wdCollapseEnd

    Do While (.Characters.Last.Information(wdHorizontalPositionRelativeToPage) - _

        .Characters.First.Information(wdHorizontalPositionRelativeToPage)) < SngWdth

      .InsertAfter Chr(151)

    Loop

    .Font.ColorIndex = wdRed

    .Font.Bold = True

    .FitTextWidth = SngWdth

  End With

End With

Set Fld = Nothing: Set Rng = Nothing

Application.ScreenUpdating = True

End Sub

An advantage of the above code is that it makes no changes to the underlying content (i.e. that content is not added to a field) and the content being struck out can therefore be in any mix of fonts, point sizes, colours, bolding, etc., without the code impacting it. Instead, the code inserts an ADVANCE field that shifts the starting point for the next character to where the first selected character starts, then pads the subtracted space out again with a set of bolded em-dashes whose width it scales down if necessary.

It colorizes the whole string mimicking the original string, kind of destroying it: No strikethrough is seen actually. I may have pushed it too hard so far. I have to use a color pen on hard copies until somehow there is a solution from somewhere.  Thank you for your perseverance, but it doesn't work. Much obliged.

Yes, it colorizes the underline just fine. My initial inquiry was for the color of the strikethrough line, not the underline line. I apologize for the misunderstanding and appreciate your kind efforts. Happy New Year!

As Suzanne pointed out though, there is a simple non-macro method for setting the underline colour. The second macro I posted is for coloured strike-throughs and addresses the original topic of this thread. Since that macro, too, employs an EQ field, the same limitations apply.

Yes, it colorizes the underline just fine. My initial inquiry was for the color of the strikethrough line, not the underline line. I apologize for the misunderstanding and appreciate your kind efforts. Happy New Year!