Racing was initially delayed by two hours due to the weather before a non-racing medical emergency in Kirk Michael and a road traffic collision at Ginger Hall pushed the schedule back further.
Organisers said that further rain forecasted until 18:00 meant the use of the evening’s contingency sessions has been ruled out.
As a result a solo practice session, which was set to take place following the Sidecar race, has also been scrapped.
The 2025 event around the 37.7-mile (61km) Mountain Course has been plagued with weather delays since it began on 26 May.
Organisers have confirmed that the postponed second Sidecar race would now take place as part of Friday’s schedule, but remain reduced to two laps.
