Instead of showing the company's trendy new commercials dappled in the new corporate colours of blue and "living orange" (don't ask), the screen remained resolutely blank.
Even this cock-up was nothing compared to some of the jaw-dropping failures owned up to by Sainsbury's management. Here was a company once considered a byword for quality and customer reassurance admitting that two-thirds of its stores are simply not up to scratch. Too many of its sites are outdated, too small and operating with tatty, clapped-out equipment (the chief executive's own words.)
If redemption is to be found in the recognition of past mistakes then this represents progress. What is breathtaking is that it took management so long to realise these failings.
The kitchen sink operation Dino Adriano embarked on yesterday involving some 1,600 job losses and pounds 160m of cost reductions is the kind of exercise that normally accompanies a new broom.
But Mr Adriano has been chief executive for a year and he has been running the UK supermarket business since 1996. You have to ask which stores he has been visiting.
The list of belated improvements includes at least one U-turn and several other initiatives shamelessly lifted from the management handbooks of Tesco and Asda.
Sainsbury's decision to offer more non-food lines is a complete reversal of its strategy only a year ago while the initiatives to start calling staff colleagues and reduce queue sizes are borrowed respectively from Asda and Tesco.
There is nothing wrong with emulating your more successful counterparts and the City gave a cautious welcome to the plans. The proof, however, will be in the implementation and Sainsbury's record here is not good.
This is a brutally competitive industry and Sainsbury's is not the only one hurting. The family may no longer have a seat on the board but they are significant shareholders and may find themselves searching for a new management team or a European suitor if the latest facelift backfires as badly as yesterday's floorshow.