In the new SAS Enterprise Guide 4.2 Project, I have found that before making modifications to a reopened project, run the process flow once (or through to that particular point) so the necessary work data table is available. Certain tasks, if opened when the work table doesn't currently exist, will create errors in the project or limit your ability to make modifications to the tasks.

1. Save a EG Project
2. Take the weekend off
3. Reopen the EG Project

Instead of moving right to #4 below, run the process flow first (at least the steps to generate the work table that the task requires)!

4. Make changes in a task that uses a work table

So some additional strategies - if your project takes a long time to generate that work table, save in another library 'temp' location. Just remember once the project is 'production' switch from a 'temp' location to the saslibref work so file space isn't an issue.