It all started with a very panicked phone call, one of our customers was exceptionally worried - she had been deleting files from her computer and then realised that they were no longer available on her iPhone.... And it took me a while to register that last part... On her phone..? Oohhh and then it hit me - the company in question were using DropBox!So, rewind several weeks, and a local company who have no IT experts amongst their staff needed a way to share their standard corporate documents with a new office in Belfast, budget was a real issue, and a VPN was out of the question, so I had recommended  that Dropbox would be a good solution. It was diligently installed on their server and done so well, that none of the staff noticed any changes (something that would turn out not to be a good thing) - they still accessed their documents through the mapped drive to "Shared staff documents" on their computers.But things did not end there - unknown to us the company director and one member of staff didn't quite understand the concept (fault of not explaining it properly entirely mine) and after I had left the site, they downloaded dropbox and put it on their own machines.... Which don't have sufficient hard disk space to store the 30Gb+ of documents that were then synchronised across the network to their pcs. The first signs of concern was an email saying that the network was running very slowly, but a different local it person visited the site and rebooted the server, and suddenly all was well... (as it turns out, really not well - the dropbox service hadn't started, so it appeared to have worked, but the moment anyone logged on to the server it started the service again...)To resolve the mounting issue of lack of disk space the staff with locally installed started deleting documents from the new local dropbox folder.... And that is when the disaster started taking hold.... Nearly 3Gb of documents permanently deleted in moments... Everywhere, in every office... Gone.Thankfully the panicked phone call stopped all that, and order is now restored (and all documents recovered - a wonderful dropbox feature!) with a big bit of learning - training, training, training - absolutely essential!