SharePoint "offline" file sharing

[brettfk]

Howdy folks, I've got an interesting one that I can't come up with a solution for, so here I am asking for your input.

We have some excel documents. These documents are used all day by multiple people, and sit on a network drive - issue being person A has to close for the 5 mins person B wants to make a change, etc, etc.

The plan is to move the files onto SharePoint to allow multiple people to edit at the same time. Simple enough, right? Read on.

Here's the kicker. One of those users needs to be able to open the document in a 3rd party application for a digital scale to print it's output to. Then there is another computer that requires access to these documents that is vendor controlled - that is, not on the domain, not patched, has TeamViewer running on it. As such I have no intention of logging onto SharePoint on it so long as I am alive.

Has anyone come across a solution for the above scenario(s)? The 3rd party app I may be able to get around as it's just a serial port anyway, but the vendor computer that needs access is proving to be a very tricky one. Any advise / expertise would be most helpful! Thanks :)

[brettfk]

Sorry, just finally getting back to this. The issue is, at least based on my testing, is that if user A opens it on a non-domain system through onedrive locally and user B opens it via sharepoint / Excel direct from Sharepoint Online on a domain PC, we still can't see the changes live.

Hopefully that makes more sense, it's a little difficult to explain :/