The day of Football Manager 2009's release and the authentication problems players experienced led to Sports Interactive studio director Miles Jacobson's "hardest and most disappointing" day of his career.

Players experienced a raft of issues when trying to authenticate Football Manager 2009 when it was released on November 14 last year. Not only was the font used for the authentication code displayed on the manual too small for some fans to make out, but SEGA-owned developer Sports Interactive suffered no less than three denial of service attacks on the day of release, one targeted directly at its phone lines.

The problems meant that day one fans weren't able to authenticate their game for up to four hours. According to Jacobson: "That led to us working through the night on the Thursday night to try and come up with a solution that worked."

Jacobson told in an interview, to be published tomorrow, that the experience was "completely and utterly unacceptable", but the copy protection put in place prevented the game from being available online in pirated form days before release, "as all our other games have been".

He said: "But that's a tiny, tiny, tiny victory compared to the issues that people had. We did get everyone up and running on the game pretty damn quickly and people who raised customer service tickets were dealt with pretty quickly as well. I think in the 20 years that I've been working, the day of release this year, because of the issues we had with DRM, was by far and away the hardest and most disappointing day of my career."

Check back tomorrow for our interview with Sports Interactive's Miles Jacobson in full. You'll find our review of the excellent Football Manager Live here.