The default folder of my first time installed UE4 (4.8 probably) was “Users/Shared/UnrealEngine/UE_4.XX”. Code completion was fine up to now. The last good setup for me was ue4.14.3 and xcode8.1.
However, when I installed ue4.15.0 and find that it didn’t run on my macbook pro 2011 anymore because of no apple metal support. I got no choice but rolling back to ue4.14.3 . This time epic games launcher set the default installed folder to “Users/Shared/Epic Games/UE_4.14”. And then I found the code completion was broken on xcode.
I spent some time trying different version of xcode and ue4 combination and couldn’t fix the problem. Yesterday, I got the right solution finally. It was the problem of default installed path. If you got space(s) in that installed path, you would screwed up. I just installed it back to “Users/Shared/UnrealEngine/UE_4.14” and everything fine again!
PS. I got no problem with spaces on the Project folder path. The problem was on the UE4 installed path.