Japan’s abdicating emperor may cause some sort of Millennium bug

The abdication of then Queen Beatrix in 2013 went off without any major problems, but that may be different next year when the Japanese emperor abdicates. The Japanese calendar changes with a new emperor and that can crash computers, like a millennium bug.

Japan’s Emperor Akihito came to the throne in 1989, but will make way for 57-year-old Prince Naruhito on April 30, 2019. This festive event could lead to crashing computers of Japanese governments, post offices and banks, according to an analyst.

That has to do with the Japanese calendar, which is based on the eras marked by the sitting emperor. Akihito became emperor in 1989 and that coincided with the beginning of the Heisei era. The vast majority of systems and computers used in Japan today are from this era and have therefore never been tested on what happens when a new era begins.

The government will announce the name of the new era on February 24, 2019. Microsoft previously confirmed that most software has not been tested for how to handle a new era and that the consequences could be similar to those of the Millennium bug.

To avoid problems, Microsoft has included a registry placeholder in the Windows 10 Spring Creators Update so that users can discover software limitations surrounding the new era. Optionally, the value in the registry can be modified or removed if problems arise.

For example, problems can arise if the calendar does not allow navigating to a previous era and assumes that there is only one era: the current one. Also, programs may have stored future dates based on the current Heisei era, while those dates will fall into the new era. That can confuse certain algorithms.