Shoutbox

I'm not quite sure what you want though.

I use such shared docs all the time at work (everything is on a network drive there) and I don't have any problems with opening/closing/saving/etc such 'shared' docs - we do it all the time.

Whenever user A opens the Excel file, he can edit it and save it as much as he likes. And indeed, user B will only be able to open it as read-only when the doc is already opened by person A.

(if you want person B to also edit the file at the same time you need to do what matty suggested - no need for Google Docs at all. In fact Google Docs can not do what isn't already possible in Excel nativly or Office Live itself)

I don't see any use for such a 'close and save when not edited for 30mins'-macro either. In fact, it would cause you more troubles in certain scenarios.

So, can you explain more about what the problem is and what you exactly want?
Do you want the user, who has the doc open, be informed if you want to change something? Or do you want the apply the change while the doc is opened by another user? If so, you are bound to bump against syncronization problems for sure!

The only safe solution would then be to do as Matty suggested. But if you don't want to loose functionality then you are only left with a system where the user is simply informed (and nothing more!) of a pending change and it should then be up to this user to close the workbook by himself when he is done. Never ever close the workbook automatically!!!!! This is a big no-no as it will cause a lot of inconsistant data if you do that. eg: the user might be in the middle of editing and when you force-close it the data might not be edited properly yet. Then you put more data in it and you both will be left with a mangled inconsistant document in which you don't know what data is edited/correct and what data is not.

So, only after the user has done the editing and closed the workbook, you can (and must) open this edited workbook to apply your chances. This is the only (!) safe way to do what you want (from what I understand) and to keep data integrity.

So, I very strongly suggest to remove that 'close and save when not edited for 30mins'-macro and replace it with a macro which checks periodically for a notification file on the network drive. This simple notification file is the one you put there to inform the user a change is pending. It can be a simple text file containing the text you want to be shown to the user.