The Ramses Square mass trial was postponed for the fourth time on Sunday.
The 494 defendants will now stand trial at the end of March.
They stand accused of a litany of crimes including the death of one man and destruction of a police station.
The trial has been delayed due to the issues of finding a place big enough to try all 494 defendants at once.
One defendant is Ibrahim Halawa, an 18-year-old Irish citizen, who was arrested aged 17.
He is hoping to be freed under a new law allowing detained foreign nationals to stand charge in their home country, as is jailed journalist Mohammed Fahmy.
Halawa's sister Nosayba told RFI that she believes Ibrahim has a stronger case than Fahmy, who recently renounced his Egyptian citizenship in order to be deported to Canada.
The prospect of Fahmy's release had made the Halawas hopeful: "his situation should be stronger than Mohammed Fahmy's situation, because he never had an Egyptian passport, he never had an Egyptian ID, when he entered Egypt for his summer holiday, he entered with a visa in his Irish passport."
Fahmy was previously awaiting deportation after his colleague, the Australian national Peter Greste, was deported to Australia last week.
But news on Sunday that he and his Al Jazeera colleague Baher Mohammed will face a retrial on 12 February has lowered hopes of deportation for him, and perhaps also for Halawa.