How does a good manager handle the lack of following instructions/reading directives?

I'm in a position to provide ignments to people. Typically, ignments include information such as: "Don't worry if X doesn't look right. It will after so-and-so resolves a technical issue." Or, I will say, "Hold off doing this. There's been an issue discovered here that needs to be resolved before you can continue." Often, these instructions are by e-mail. Yet it seems like the information is often overlooked. People will finish ignments and say "It doesn't look right" when I told them to expect it wouldn't, or they have to re-do work they were told not to work on as a result of some technical issue that needed to be resolved first. Short of duplicating my efforts, by speaking as well as writing out my instructions, what can I do so that I don't have to say, "I told you it wouldn't look right" or "I asked you to hold off working on it until this was resolved first." Thinking these statements is annoying myself! I don't want to be a nag, but I'd like to be more effective too!