SketchUp has expired

Situation: you start SketchUp and get this message: "Your version of SketchUp has expired. Please upgrade now."

There are actually two situations in which this can happen:

• SketchUp really has expired, in which case you can download and install the new free version, and then continue using SketchUp. We expire SketchUp in this way so that we can keep it in sync with other products it works with like the 3D Warehouse and Google Earth.
  
  
• You just downloaded and installed SketchUp, and get this message the first time you try to start it. In this case, the cause is most likely that your system date is incorrect. To fix this issue:
  
  1. Uninstall SketchUp.
  2. Open the "Start" menu.
  3. Click "Control Panel."
  4. Click "Date, Time, Language, and Regional Options."
  5. Click "Change the date and time."
  6. Change the date to the current month, day, and year.
  7. Close the Control Panel.
  8. Reinstall SketchUp.