Or at least, no First Crusade success.
The Crusades are by themselves so strange that removing them seems quite easy (anything from premature death of Urban II, to more dissent between East and West so that Alexios does not call for help, or more infighting between the Latin Kingdoms).
I'm more interested in the effects of “no Crusades”: how are the Latin kingdoms going to spend all this energy? Fighting each other? (probable). Going East? (likely). Conquering Constantinople instead? (also likely). Also, how are science, math, philosophy, and civilization in general, going to develop in Western Europe without all the loot? This could perfectly develop a situation in which Muslims would be considered the true heirs to Classical Antiquity, because they kept all the books.