New Excel VBA compile error upon saving workbooks - vba

Question

I have been using the code below to successfully create and save a new workbook for each worksheet in my workbook. When I try to run it now I get an error "Compile Error Wrong number of arguments or invalid property assignments". I cannot see why it is not working now; it did before. I do want the date in the final name. If I run the code with the wb.SaveAs line marked with ' it works fine. It doesn't seem to like the format part now. Any ideas what is different and why? Thank-you.
Sub Make_Workbooks()
Dim ws As Worksheet
Dim wb As Workbook
Application.ScreenUpdating = False
Application.EnableEvents = False
Application.Calculation = xlCalculationManual
For Each ws In ThisWorkbook.Worksheets
Set wb = Workbooks.Add
'wb.SaveAs ThisWorkbook.Path & "\" & ws.Name
wb.SaveAs ThisWorkbook.Path & "\" & ws.Name & Format(Date, "yyyy-mm-dd") & ".xlsx"
ws.Copy Before:=wb.Worksheets(1)
wb.Close SaveChanges:=True
Next ws
ResetSettings:
'Reset Macro Optimization Settings
Application.EnableEvents = True
Application.Calculation = xlCalculationAutomatic
Application.ScreenUpdating = True
End Sub

Answer 1

The syntax used to use the SaveAs should be FileName, FileFormat, ....
In your code it should be:
wb.SaveAs ThisWorkbook.Path & "\" & ws.Name & Format(Date, "yyyy-mm-dd"), xlOpenXMLWorkbook
(xlOpenXMLWorkbook = ".xlsx")
If you will run your code a few times every day, you will get a message if you want to overwrite the existing file since ThisWorkbook.Path & "\" & ws.Name & Format(Date, "yyyy-mm-dd") will have the same String on the same day.
If you want to automatically overwrite your previous file, then add the line Application.DisplayAlerts = False.
Code
Option Explicit
Sub Make_Workbooks()
Dim ws As Worksheet
Dim wb As Workbook
Application.ScreenUpdating = False
Application.EnableEvents = False
Application.Calculation = xlCalculationManual
For Each ws In ThisWorkbook.Worksheets
Set wb = Workbooks.Add
' add this line to automatically overwrite the exisitng file (not getting the MsgBox on every time)
Application.DisplayAlerts = False
wb.SaveAs ThisWorkbook.Path & "\" & ws.Name & Format(Date, "yyyy-mm-dd"), xlOpenXMLWorkbook
ws.Copy Before:=wb.Worksheets(1)
wb.Close SaveChanges:=True
Next ws
ResetSettings:
'Reset Macro Optimization Settings
Application.EnableEvents = True
Application.Calculation = xlCalculationAutomatic
Application.ScreenUpdating = True
Application.DisplayAlerts = True
End Sub
Edit1: If you want to make sure 2 file names never have the same name, you can use the Now function:
wb.SaveAs ThisWorkbook.Path & "\" & ws.Name & Format(Now, "yyyy-mm-dd_hh_mm_ss"), xlOpenXMLWorkbook

Answer 2

I can't replicate your problem on my system, but the following code minimizes the explicit creation and tracking of new Workbook objects, so it may be less error-prone across different environments:
Sub Make_Workbooks()
Dim ws As Worksheet
For Each ws In ThisWorkbook.Worksheets
ws.Copy 'Copies current sheet to new workbook
ActiveWorkbook.SaveAs ThisWorkbook.Path & "\" & ws.Name & "_" & Format(Date, "yyyy-mm-dd") & ".xlsx"
ActiveWindow.Close
Next ws
End Sub