My tax files wouldn't send. I have had this Error 2 popping up all afternoon. I read many suggestions, but nothing worked. I discovered that when I opened the task manager, several files I no longer need, or use were running for the program "Dropbox". I hit end task on all Dropbox. It allowed the tax file to send immediately following this. I choose to remove the program "Dropbox", so this didn't cause me further problems.