I use Zotero to manage my references. You can download it from "https://www.zotero.org/".
After you installed the Firefox plugin or standalone version install the word add on.
I use the Zotero button to download citation and paper from the journal websites lie IEEE and science direct. It is amazing.
I changed the data folder of Zotero in standalone and I received error whenever I tried to save a paper using the before mentioned method. I noticed that I didn't change the data folder on my Zotero Firefox and after that it resolved my problem.
You can buy space from Zotero to support them (preferred), but if you can,t do it now consider using a Dropbox folder for your data. I am using Zotero on 4 computers.