South African Ryan Sean Davy, 43, claims to have climbed alone to a height of 7,300m (24,000ft) before he was found hiding in a cave.
He has apologised but complained of being treated "like a murderer".
It is extremely rare for someone to attempt climbing Everest by themselves.
The overwhelming majority of climbers only tackle the highest mountain in the world with the help of at least one guide and a well-equipped support team at base camp.
