The third problem is hidden in data. The answer depends on the spreadsheet being used. These two popular spreadsheets provide different answers and very little documentation. As long as customers of these systems enter data in its abbreviated two-digit year form, there will be a year 2000 problem when those dates are compared to other dates after the year 2000. Technically the year 2000 problem is not very challenging.
Several techniques are available to help embedded process controllers.
What makes the problem difficult is two related issues. One, many different areas must be examined and fixed. Invalid date comparisons can occur in computer programs, training, embedded processors, and in existing data. This becomes a massive inventory, remediation, and testing campaign. In short, it requires an extensive management effort to prioritize and execute a plan that will avert problems in time.