Excel: How Do I Remove All Carriage Returns from a Cell?

Assuming your cell is in A1, you can use the following formula:

=SUBSTITUTE(A1,CHAR(10),"")

Depending on the carriage return, you may have to use char(13) instead of char(10).

=Clean(A1)

This command can be found in Excel under the formulas tab > text.

Select the cell or cells, click Data/Text To Columns form Excel's menu bar, choose the Delimited option on the first dialog page, click the Next button, uncheck everything except Other and type Ctrl+J into the field next to it (you won't see anything in that box, but the column layout chart will show that it is being split at the line feeds (they are not carriage returns)... then just click the Finish button.

Sub RemoveLineBreaks()
    Application.ScreenUpdating = False
    Dim rngCel As Range
    Dim strOldVal As String
    Dim strNewVal As String

    For Each rngCel In Selection
        If rngCel.HasFormula = False Then
            strOldVal = rngCel.Value
            strNewVal = strOldVal
            Debug.Print rngCel.Address

            Do

            strNewVal = Replace(strNewVal, vbLf, " ")

            If strNewVal = strOldVal Then Exit Do
                strOldVal = strNewVal
            Loop

            If rngCel.Value <> strNewVal Then
                rngCel = strNewVal
            End If
        End If
        rngCel.Value = Application.Trim(rngCel.Value)
    Next rngCel
    Application.ScreenUpdating = True
End Sub