The trial of 25 activists, including Alaa Abdel-Fattah, over an authorised protest has been adjourned until 11 June.
It was the first session of the trial after Abdel-Fattah's request for the judge to be replaced was rejected.
According to lawyer Mohamed Abdel-Aziz, the judge overseeing the case was absent because he had the flu.
On 23 March, Abdel-Fattah and Ahmed Abdel-Rahman, another defendant, were released on bail of LE10,000 each.
The 25 defendants face charges of illegal protesting, attacking a public employee whilst doing his job, sabotaging public property, attacking Captain Emad Tahoon and stealing his two-way radio.
The charges relate to a protest against military trials for civilians outside the Shura Council in Cairo in November 2013.
The protest was the first to be dispersed by force in accordance with a controversial protest law issued in the same month, which criminalises unauthorised public demonstrations.
The No to Military Trials group claimed responsibility for organising the protest, but Abdel-Fattah was charged with being the protest organiser.