If you are using Dropbox and Git, this may increase the size of your manuscript folder to the point where our book generators start having trouble retrieving data from your manuscript  folder when you try to preview or publish. (If you are having this problem, you will notice that our book generators slow down or stop when they get to Step 5.) The solution is to use the Selective Sync option in Dropbox to omit the .git  folder, which will probably be hidden when you look in the manuscript  folder on your computer.