Let's get down to BASICS ...
and fix the shortcuts.
Right click on EACH of the shortcuts and then select PROPERTIES. Tell us what EACH says about the shortcut's properties since they will point to the file that is to be executed.
If, for example the shortcut's properties says something like C:\batch_files\Outlook_back.bat then we would know to look at the batch file indicated to see what the problem is.
If these external drives were disconnected at some point and got assigned different drive letters that too could cause the shortcut to not work.
It is up to YOU to tell us SPECIFICS about the shortcuts and not make us guess about your abbreviations.