Work with Workbooks.Open Method to open it in in the background, and hide any alerts with Application / ScreenUpdating / EnableEvents / DisplayAlerts
Application.ScreenUpdating Property (Excel) Turn screen updating off to speed up your macro code. You won't be able to see what the macro is doing, but it will run faster.
Example
Sub CopySheets1()
Dim wkb As Workbook
Dim sWksName As String
With Application
.ScreenUpdating = False
.EnableEvents = False
.DisplayAlerts = False
End With
wkb Workbooks.Open("C:\temp\bookname.xls")
sWksName = "SHEET NAME"
For Each wkb In Workbooks
wkb.Worksheets(sWksName).Copy _
Before:=ThisWorkbook.Sheets(1)
Next
With Application
.ScreenUpdating = True
.EnableEvents = True
.DisplayAlerts = True
End With
Set wkb = Nothing
End Sub
Assuming your folder name is C:\Temp\
then Loop until folder returns an empty
Example
Dim FileName As String
' Modify this folder path as needed
FolderPath = "C:\Temp\"
' Call Dir the first time to all Excel files in path.
FileName = Dir(FolderPath & "*.xl*")
' Loop until Dir returns an empty .
Do While FileName <> ""
' Open a workbook in the folder
Set wkb = Workbooks.Open(FolderPath & FileName)
'--->> Do your copy here
' Close the source workbook without saving changes.
wkb.Close savechanges:=False
' next file name.
FileName = Dir()
Loop
Use a Do...Loop structure when you want to repeat a set of statements an indefinite number of times, until a condition is satisfied. If you want to repeat the statements a set number of times, the For...Next Statement is usually a better choice.