The mass exodus of BlackBerry executives continues. According to The Wall Street Journal, David J. Smith, the executive who led the team that created the failed PlayBook tablet, has left the company. A BlackBerry spokesperson confirmed the report, noting that he “resigned for personal reasons.” Despite releasing two new smartphones running its new BlackBerry 10 operating system, BlackBerry has continued to struggle in the mobile market and recently lost 4 million subscribers. The company recently fired its U.S. sales chief, and a number of other high-level executives have left BlackBerry in recent weeks. The PlayBook failed to compete against the iPad and Android tablets when it was released in 2011, leading BlackBerry to write off nearly $500 million in unsold inventory. The company would later end support for the PlayBook, announcing that the device will not be updated to BlackBerry 10.