Hi! I have created a power shell script that opens three instances/threads of excel. One of the threads are responsible for the other two threads and communicates with them via a text file. Here is a sample of how each excel application is created: Set objExcel = CreateObject("Excel.Application") Set objWorkbook = objExcel.Workbooks.Open("XX.xlsm") objExcel.Application.DisplayAlerts = True objExcel.Application.Visible = False objExcel.Application.Run ExampleFcn objExcel.ActiveWorkbook.Close objExcel.Application.Quit objExcel.Quit Set objWorkbook = Nothing Set objExcel = Nothing WScript.Quit Every new day the master thread creates a new folder and write to the text file that its time to save current workbook and create a copy (in the new folder) and continue in the new folder. These commands are used: ThisWorkbook.Save ThisWorkbook.SaveCopyAs nameFullFilePath But almost every day I get an error msg: - error code: 1004 Microsoft excel cannot access the file .\pathToWorkbook\6DED7E10 I have implemented a for loop with "on error resume next", to try several times, and it works the next time it attempts to save. So my question is: what is the 6DED7E10 file/folder? Has it something to do with the WScript, or something to do with the new created folder, maybe it takes too long time to create the folder and the other threads are too quick? Any ideas? Best Regards Olle