For my scientific writing I’m using Zotero to keep track of the bibliographical data of everything I read and of all the references in my own documents. I suppose everybody does that. Or at least I hope so – for your own best! If you don’t, you should start. And if you’re using commercial packages like EndNote to do that you should consider changing to Zotero and doing something useful with the money you save. Seriously.
Anyways, I had been using the cloud storage service
box.net to store the liked documents (mostly PDF files) cataloged in my Zotero database from early 2011 and hadn’t touched my Zotero configuration since then. This setup had been working flawlessly for almost three years now. It was only today that I noticed that tiny red exclamation mark in the upper right corner of the Zotero interface, which informed me that something with my synchronization wasn’t working anymore.