It's pretty simple: the Prophet of Islam dies in the subjugation of the polytheists of the Peninsula or shortly thereafter. While his relatives were fervent enough to keep conquering even after his death, it's unlikely that they would have had the same drive if had lacked of the itme for make a plan for future spreading of Islam. That, or the Sasanids and Byzantines decide to team up and push the Islamic invaders back, but it's a lot more unlikely
The Levant may stay Christian indefinitely, which, aside from cancelling the Crusades (barring major heresies in the area) and thus butterflying away or procrastinating the rise of Italian Marinary Republics and making the Fourth Crusade merely an European pillage of Costantiople in the name of money and land (as it was IOTL, but this time with an explicit intent).
A Christian North Africa will obviously make so that Sicily will get invaded only by the Normans, and make Charles V's efforts against Barbary Pirates something of a fight just against pirate states because they were pirate states (as opposed to states inhabited by heathens).
The Africa Horn sounds like a place where the Coptic Church will thrive and spread around. If the Scramble for Africa will ever come, I think that there would be lots of Ethiopias around
Iran will stay Zoroastrian and put. You may see the occasional Madzakist or Manicheian dynasty/state, but otherwise they will stay so.
Turkey will be either fragmented after the inevitable all of the Byzantines, or remain united under one flag of a Christian equivalent of the Ottomans.
I don't know enough about Malaysia and Indonesia for have an informed opinion on the subject.