Selecting workbook to run macro

[Admin]

Hi

No need to activate. Try to explicitly dim the variables. Try something like

Dim wbkSource   As Workbook
Dim wbkTarget   As Workbook
Dim wksSource   As Worksheet
Dim wksTarget   As Worksheet
Dim rngTarget   As Range


Set wbkSource = ThisWorkbook
Set wbkTarget = Workbooks("Mydata") 'The 'Mydata' workbook must be open

Set wksSource = wbkSource.Worksheets("Sheet1")
Set wksTarget = wbkTarget.Worksheets("Data")
Set rngTarget = wksTarget.Range("A1")

wksSource.Range("A1:D10").Copy rngTarget