VBA copies the workbook into the Excel XLSTART startup folder

Anything in the Excel XLSTART startup folder loads automatically every time Excel starts. A macro that writes a copy of its own workbook into Application.StartupPath is establishing persistence — the hallmark of a resident Excel macro virus (Laroux/"StartUp" lineage) rather than a normal document. Detected by a SaveAs/SaveCopyAs whose target is Application.StartupPath.