Lots of things can go wrong while Sabayon unpacks a user profile, collects changes made to the configuration, packs the profile again, etc.  We use several helper procesess (sabayon-apply inside sabayon-session inside sabayon), and when an error occurs in one of them, the user often doesn't see the error.  We could use this information to make Sabayon more robust - either by fixing the bug which caused the error, or by handling that error condition gracefully.

The helper programs (sabayon-session, sabayon-apply) could exit with well-defined codes, which the parent process (sabayon) could use to present a meaningful error dialog to the user.  Something like

  exit(1) - means the child exited abnormally due to an unhandled exception
  exit(2) - means sabayon-apply could apply *most* of the profile, but it failed in some sections
  etc.

Then for (2) we could gather the exceptions from the failed bits and print them out nicely.