Simultaneous accesses to 0x1c0a7f0f8, but modification requires exclusive access error on Xcode 9 beta 4

Question

my project uses both Objective-C and Swift code. When a user logs in, it calls a set of apis for user preference, I have a DataCoordinator.swift class which schedules the AP

Answer 1

Only in Swift 4 and when using .initial option for your KVO Settings

If you check your context in observeValue method, just make your context variable static. This blog post describes this bug in detail.