Way back when I was in IT Admin, I used to have this problem all the time. Some non-tech person emails a spreadsheet, another non-tech person edits it, and saves it. The original person complains that they can't see the changes. Yeah, because it's saved in some MS Windows Profile location that no sane human would ever visit. My solution was to ONLY email links to shared files on a shared resource. The LAST thing I'd ever think of is writing software to solve this problem!

These days if I were interviewing someone and they said, "I'd use the simple solution that is fairly ubiquitous", I'd say, "yes! you've now saved yourself tons of engineering hours - and you've saved the company eng money".

I attach a copy of the file and then provide a network location for where it is located. Makes it easy for people to just open up a simple copy to look at it and they know where to go to access the original.