Been using Excel for many years, on my Mac, version 12.3.6. No problems with it, but in the last year have had trouble saving my master worksheet. I use one sheet for all my client information, titled Clients.xls, and now every time I add data and try to save it, it insists on naming it a new title, Clients 1.xls; or any consecutive number. I don't want to retitle my file. What do I do?

Also, I'm not able to put an alias for my Clients file in my dock, or in Finder Favorites. Why is this?