at our association we are running Windows Server 2012 Essentials, so that our members can log on with their own accounts.
Recently, it happened that someone didn't log off their Dropbox account and when someone else logged on, he could access the account of the other. This has now happened twice, but never before (at least that I know). It also happened only with Dropbox (not with other serices - as said: AFAIK) and only with Firefox.
Probably the biggest problem is that I can't reproduce the problem. I've tried several times now logging in with my own account and then letting someone else log in on that PC. However, on his account Dropbox then was always logged off or he was himself logged in with his account (that was when he didn't log off the last time he used Dropbox - which is the right behaviour).
I know this is a really vague problem, so my question is really: What can I do to find out more about the problem? Is there something I could to to be able to reproduce the problem? Is there something else I could try?
I'm really glad for every help I get!