I'm getting a runtime error '13':
Type Mismatch

The code is:

Function UsageLog_1()

' Stores who and when on Sheet1, column C
Sheets("UsageLog").Select

If Range("C5600").End(xlUp).Row = 1 And Range("C5600").End(xlUp).Value =
"" Then <===== This is the line which is highlighted for the error
Range("C5600").End(xlUp).Value = "Last opened by " &
Environ("username") & " at " & Now
Exit Function
End If

Range("C5600").End(xlUp).Offset(1, 0).Value = "Last opened by " &
Environ("username") & " at " & Now

ThisWorkbook.Sheets("COVER").Activate
End Function

Thanks in advance