Can You Cover Your Head While Sleeping in Ihram?
Question

Is it permissible for the Muhrim (pilgrim in Ihram) to cover his head when sleeping?
Praise be to Allah.Shaykh Ibn `Uthaymin (may Allah have mercy on him) said:
“If the pilgrim is a female, then it is well known that it is permissible for her to cover her head. But if the pilgrim is a man, that is not permissible when he is sleeping or when he is awake. But if he covers it (unintentionally) while he is asleep, then when he wakes up he must uncover his head, and he does not have to do anything else, because the Pen is lifted from the one who is asleep.” (Majmu` Fatawa Ibn `Uthaymin, 22/ 128)
For more details, please see the following answers: 11356 , 26724 , 175014 , 227097 , 41140 . 
And Allah knows best.