Yesterday's ruling was made by the Takeover Panel after United's chief executive, David Gill, said there was concern over the effect of the uncertainty on the club's future.
Glazer's second bid - amounting to around $800million at 300p per share - is said to involve less debt and a fund of $20million for new players, as well as backing for the expansion of Old Trafford.
Yet the board still remain concerned at the level of debt involved and the club's supporters remain strongly opposed to any approach from Glazer.
Glazer will nevertheless be reluctant to pull out entirely, given the downturn in the share price that would follow and the fact he has already borrowed £200million.
The American tycoon already has a 28.1 per cent holding in soccer's richest club.
