Why do I have to do a saveas before excel vba shell and wait program works

Question

I am using an excel vba program to open either a .exe or .bat file. Because I have to wait for the external program to finish before I can continue I am using shell and wait methods I have come across on different user forums. However, independent of the module I use for shell and wait, I cannot open my spreadsheet and run the code directly. I have to do a manual saveas and rename the file; which after doing so my vba code works perfecrtly.

Thanks