When moving or copying a sheet by selecting its tab (that is, by right-clicking, and then selecting Move or Copy from the shortcut menu), unwanted links can be created in the new workbook if the copied sheet contains Named Cells.

Broken links are created when the location of the precedent workbook is changed on the hard disk.

If you save a workbook that is linked to another workbook and then move or copy the linked workbook to another folder on the hard disk, the first workbook will (erroneously) refer to the original reference location.