Multiple Users in a Macro enabled Excel Doc

Hi Folks,

I had a situation over the weekend that caused major headaches for a bunch of people today.

The root cause was that multiple people were in a macro enabled excel doc located on SharePoint. Since they were all trying to use the macro at once, it caused a secondary file to break.

Is there a way in VBA to tell if multiple people are or another person is using the file and throw a message box up warning the new user of this when the workbook opens? I figure it can be tied to the workbook_open macro.

Since the macro file is on SharePoint, their initials are already showing up in the top right corner, but people aren't looking out for it.

I guess the best example is when a file isn't on SharePoint and multiple people open it. The second person is forced to a read only version.

A second issue is that the file was opened in the web viewer instead of the desktop app. Is there a way to force the user to open the macro file in the app? I want them not to be able to open it in the web viewer.

thanks for the help,

Mike