Steve Milligan was ready to declare victory. A statement was drafted and a photographer was getting lined up for a handshake ceremony planned in Tokyo. As the brash Silicon Valley executive prepared to announce the biggest deal of his career, a prominent Japanese newspaper was reporting his consortium had clinched an agreement to buy Toshiba Corp.'s semiconductor unit, the country's last big chip business.

Except that they hadn't. Before Milligan could strike a pose for the cameras, the deal was off. For the chief executive officer of Western Digital Corp., it was the latest misread in a string of them.

When Toshiba put its chip unit on the auction block eight months ago, Milligan's team seemed to have some advantages over deeper-pocketed rivals. As Toshiba's partner in the memory business, it had legal leverage that could be used to scare other bidders away. Toshiba faced staggering losses from its bankrupt nuclear reactor business and was being pressured by lenders to close a deal quickly.