Reading revealed Steve Coppell as their new manager on Thursday.
Coppell, who was widely believed to be Reading's first choice for the job, moves from Brighton to succeed Alan Pardew and has signed until the end of the 2004-5 season.
It had been predicted the Royals would have a new manager installed by Wednesday at the latest.
But Brighton chairman Dick Knight revealed the Berkshire club had been forced to scrap a planned news conference after failing to finalise negotiations with the former Crystal Palace manager.
Knight told the Reading Evening Post newspaper: "Steve is clearly still negotiating with them because they cancelled a scheduled press conference for Tuesday afternoon."
He added: "Steve knows where this club stands. We want him to stay, but he's got to make his decision quickly.
"Clearly this impasse cannot go on for us or Reading."
Reading refused to elaborate on the story, standing by their policy of not naming individual targets for their vacant management role.
Coppell's first game in charge would be at home to Gillingham next Tuesday.
The Berkshire side's visit to Burnley on Saturday has been postponed because of international commitments.
The Royals had been searching for a new manager since Pardew controversially quit to join Division One rivals West Ham last month.
The likes of George Graham, Glenn Hoddle and Tony Adams were initially linked with the vacancy, but Reading opted for the experienced Coppell.
He takes over with the Royals in mid-table after a run of just one win from six league matches under caretaker boss Kevin Dillon.