Unrecognized Selector Sent To Instance

iOS

TL;DR

Unrecognized Selector Sent To Instance indicates a dependency failure on iOS that interrupts the current user flow.

Symptoms

Unrecognized Selector Sent To Instance appears in crash logs
The app exits or the UI flow stops

Common Causes

Required symbol, class, or asset is missing
Build or runtime linkage is inconsistent

How to Verify

Reproduce with deterministic input and capture full logsInspect the first throw site and recent changes around it

Quick Fixes

Add guard checks and a safe fallback path
Disable or rollback the risky code path behind a flag

Proper Fixes

Enforce contracts with types, runtime checks, and tests
Refactor ownership and lifecycle boundaries to remove the failure mode

Example Stack Trace

Unrecognized Selector Sent To Instance in ProfileViewController.swift:42

Related Errors

IllegalStateException Unhandled Promise Rejection Hydration Failed