Error when saving a new file using SaveAs function in vba - excel

Question

I am accepting a date from Input Box and filtering my data and saving it in a new workbook. When I am saving this new workbook, its giving me a Run-time error 1004 with a sentence as:
Method 'SaveAs'of object'_Workbook' failed.
I am unable to find a solution to this.
Sub GIACTSDS121()
Dim dte As Date
mBox = InputBox("Enter a date")
If IsDate(mBox) Then
dte = CDate(mBox)
Dim Lastrow As Long
Lastrow = ActiveSheet.Range("A" & Rows.Count).End(xlUp).Row
ActiveSheet.Range("A1:AC" & Lastrow).AutoFilter Field:=2, Criteria1:=">=" & dte, _
Operator:=xlAnd, Criteria2:="<" & dte + 1
Range("U1").Select
ActiveSheet.Range("A1:AC" & Lastrow).AutoFilter Field:=21, Criteria1:="Yes"
Range("A1").Select
Range(Selection, Selection.End(xlDown)).Select
Range(Selection, Selection.End(xlToRight)).Select
Selection.Copy
Workbooks.Add
ActiveSheet.Paste
ActiveSheet.Range("A:A,E:E,I:I,M:N,Q:T,X:Z").EntireColumn.Delete
ActiveWorkbook.SaveAs Filename:="K:\K_Drive\RP\RPS-Metrics-ops\' Operations Metrics\Investigation Documentation\GIACT Investigations\SDS_Cases\_" & dte & ".xlsx", FileFormat:=51
ActiveWorkbook.Close
Else
MsgBox "This is not a date. Please try again"
End If
End Sub

Answer 1

The Filename parameter passed to SaveAs contains an invalid character that windows does not accept for a filename
Filename:="K:\K_Drive\RP\RPS-Metrics-ops\' Operations
^
|
maybe this is the cause!

Answer 2

Get rid of all ActiveSheet, ActiveWorkbook and all .Select if possible (see How to avoid using Select in Excel VBA).
Also specify a worksheet for every object that is located in a worksheet like Range, Cells, Rows, Columns.
Public Sub GIACTSDS121()
Dim ws As Worksheet
Set ws = ActiveSheet 'better define by name as: Set ws = ThisWorkbook.Worksheets("Sheet1")
Dim mBox As Variant
mBox = InputBox("Enter a date")
If IsDate(mBox) Then
Dim dte As Date
dte = CDate(mBox)
Dim LastRow As Long
LastRow = ActiveSheet.Range("A" & ws.Rows.Count).End(xlUp).Row
ws.Range("A1:AC" & LastRow).AutoFilter Field:=2, Criteria1:=">=" & dte, _
Operator:=xlAnd, Criteria2:="<" & dte + 1
ws.Range("A1:AC" & LastRow).AutoFilter Field:=21, Criteria1:="Yes"
ws.Range(ws.Range("A1"), ws.Range("A1").End(xlDown).End(xlToRight)).Copy
Dim NewWb As Workbook
Set NewWb = Workbooks.Add
NewWb.Worksheets(1).Paste
NewWb.Worksheets(1).Range("A:A,E:E,I:I,M:N,Q:T,X:Z").EntireColumn.Delete
NewWb.SaveAs Filename:="K:\K_Drive\RP\RPS-Metrics-ops\' Operations Metrics\Investigation Documentation\GIACT Investigations\SDS_Cases\_" & dte & ".xlsx", FileFormat:=51
NewWb.Close SaveChanges:=False
Else
MsgBox "This is not a date. Please try again"
End If
End Sub