diff --git a/.swiftpm/xcode/xcshareddata/xcschemes/Reducer.xcscheme b/.swiftpm/xcode/xcshareddata/xcschemes/Reducer.xcscheme
index 46117df..c81fbb9 100644
--- a/.swiftpm/xcode/xcshareddata/xcschemes/Reducer.xcscheme
+++ b/.swiftpm/xcode/xcshareddata/xcschemes/Reducer.xcscheme
@@ -77,6 +77,16 @@
                ReferencedContainer = "container:">
             </BuildableReference>
          </TestableReference>
+         <TestableReference
+            skipped = "NO">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "ReducerMacroTests"
+               BuildableName = "ReducerMacroTests"
+               BlueprintName = "ReducerMacroTests"
+               ReferencedContainer = "container:">
+            </BuildableReference>
+         </TestableReference>
       </Testables>
    </TestAction>
    <LaunchAction
diff --git a/Sources/Reducer/Reduce.swift b/Sources/Reducer/Reduce.swift
index 112feca..8f1eb3a 100644
--- a/Sources/Reducer/Reduce.swift
+++ b/Sources/Reducer/Reduce.swift
@@ -17,6 +17,7 @@ public protocol Reduce: AnyObject {
     var initialState: State { get }
     
     func start() async throws
+    func error(_ error: any Error, action: Action) async
 
     func mutate(action: Action) async throws
     func reduce(state: State, mutation: Mutation) -> State
@@ -29,6 +30,8 @@ public extension Reduce {
     
     func start() async throws { }
     
+    func error(_ error: any Error, action: Action) async { }
+    
     func shouldCancel(_ current: Action, _ upcoming: Action) -> Bool {
         false
     }
@@ -77,6 +80,7 @@ open class ProxyReduce<R: Reduce>: Reduce {
     public var initialState: State
     
     private let _start: ((@escaping (Mutation) -> Void) async throws -> Void)?
+    private let _error: ((@escaping (Mutation) -> Void, any Error, Action) async -> Void)?
     private let _mutate: ((State, Action, @escaping (Mutation) -> Void) async throws -> Void)?
     private let _reduce: ((State, Mutation) -> State)?
     private let _shouldCancel: ((Action, Action) -> Bool)?
@@ -85,6 +89,7 @@ open class ProxyReduce<R: Reduce>: Reduce {
     public init( 
         initialState: State,
         start: ((@escaping (Mutation) -> Void) async throws -> Void)? = nil,
+        error: ((@escaping (Mutation) -> Void, any Error, Action) async -> Void)? = nil,
         mutate: ((State, Action, @escaping (Mutation) -> Void) async throws -> Void)? = nil,
         reduce: ((State, Mutation) -> State)? = nil,
         shouldCancel: ((Action, Action) -> Bool)? = nil
@@ -92,6 +97,7 @@ open class ProxyReduce<R: Reduce>: Reduce {
         self.initialState = initialState
         
         self._start = start
+        self._error = error
         self._mutate = mutate
         self._reduce = reduce
         self._shouldCancel = shouldCancel
@@ -103,6 +109,9 @@ open class ProxyReduce<R: Reduce>: Reduce {
             start: { _ in
                 try await reduce.start()
             },
+            error: { _, error, action in
+                await reduce.error(error, action: action)
+            },
             mutate: { _, action, _ in
                 try await reduce.mutate(action: action)
             },
@@ -126,6 +135,10 @@ open class ProxyReduce<R: Reduce>: Reduce {
         try await _start?({ [weak self] mutation in self?.mutator?(mutation) })
     }
     
+    public func error(_ error: any Error, action: Action) async {
+        await _error?({ [weak self] mutation in self?.mutator?(mutation) }, error, action)
+    }
+    
     open func mutate(action: Action) async throws {
         try await _mutate?(currentState, action, { [weak self] mutation in self?.mutator?(mutation) })
     }
diff --git a/Sources/Reducer/Reducer.swift b/Sources/Reducer/Reducer.swift
index ed0c85a..268c769 100644
--- a/Sources/Reducer/Reducer.swift
+++ b/Sources/Reducer/Reducer.swift
@@ -115,7 +115,11 @@ open class Reducer<R: Reduce>: ObservableObject, Mutable {
             action,
             with: Task { @MainActor in
                 // Mutate state from action.
-                try? await reduce.mutate(action: action)
+                do {
+                    try await reduce.mutate(action: action)
+                } catch {
+                    await reduce.error(error, action: action)
+                }
             }
         ))
     }
diff --git a/Tests/ReducerTests/Model/ErrorReduce.swift b/Tests/ReducerTests/Model/ErrorReduce.swift
new file mode 100644
index 0000000..119a962
--- /dev/null
+++ b/Tests/ReducerTests/Model/ErrorReduce.swift
@@ -0,0 +1,54 @@
+//
+//  ErrorReduce.swift
+//  Reducer
+//
+//  Created by JSilver on 11/3/24.
+//
+
+import Foundation
+import Reducer
+
+@Reduce
+@MainActor
+class ErrorReduce {
+    enum Action {
+        case occurError(any Error)
+    }
+    
+    enum Mutation {
+        case setCount(Int)
+    }
+    
+    struct State {
+        var count: Int
+    }
+    
+    let initialState: State
+    
+    init() {
+        self.initialState = State(
+            count: 0
+        )
+    }
+    
+    func error(_ error: any Error, action: Action) async {
+        mutate(.setCount(currentState.count + 1))
+    }
+    
+    func mutate(action: Action) async throws {
+        switch action {
+        case let .occurError(error):
+            throw error
+        }
+    }
+    
+    func reduce(state: State, mutation: Mutation) -> State {
+        var state = state
+        
+        switch mutation {
+        case let .setCount(count):
+            state.count = count
+            return state
+        }
+    }
+}
diff --git a/Tests/ReducerTests/Model/TestError.swift b/Tests/ReducerTests/Model/TestError.swift
new file mode 100644
index 0000000..421c4c4
--- /dev/null
+++ b/Tests/ReducerTests/Model/TestError.swift
@@ -0,0 +1,16 @@
+//
+//  TestError.swift
+//  Reducer
+//
+//  Created by JSilver on 11/3/24.
+//
+
+import Foundation
+
+struct TestError: Error {
+    let description: String
+    
+    init(_ description: String) {
+        self.description = description
+    }
+}
diff --git a/Tests/ReducerTests/ReducerTests.swift b/Tests/ReducerTests/ReducerTests.swift
index e1393ce..1bf1797 100644
--- a/Tests/ReducerTests/ReducerTests.swift
+++ b/Tests/ReducerTests/ReducerTests.swift
@@ -9,6 +9,7 @@ import XCTest
 @testable import Reducer
 import Combine
 
+@MainActor
 final class ReducerTests: XCTestCase {
     // MARK: - Property
     
@@ -22,7 +23,6 @@ final class ReducerTests: XCTestCase {
     }
     
     // MARK: - Test
-    @MainActor
     func test_that_count_increases_when_receiving_increase_action() async throws {
         // Given
         let reducer = Reducer(
@@ -46,7 +46,6 @@ final class ReducerTests: XCTestCase {
         XCTAssertEqual(result, [0, 1, 2])
     }
     
-    @MainActor
     func test_that_count_does_not_mutate_when_receiving_same_action_twice() async throws {
         // Given
         let reducer = Reducer(
@@ -70,7 +69,6 @@ final class ReducerTests: XCTestCase {
         XCTAssertEqual(result, [0, 1])
     }
     
-    @MainActor
     func test_that_all_action_cancelled_when_reducer_deinit() async throws {
         // Given
         var reducer: Reducer<CountIncreaseReduce>? = Reducer(
@@ -96,7 +94,6 @@ final class ReducerTests: XCTestCase {
         XCTAssertEqual(result, [0])
     }
     
-    @MainActor
     func test_that_count_increases_when_mutate_in_start() async throws {
         // Given
         let reducer = Reducer(TimerReduce(
@@ -113,7 +110,6 @@ final class ReducerTests: XCTestCase {
         XCTAssertGreaterThan(result.last ?? 0, 0)
     }
     
-    @MainActor
     func test_that_count_increases_when_await_mutate_in_start() async throws {
         // Given
         let reducer = Reducer(AwaitStartReduce(
@@ -130,7 +126,6 @@ final class ReducerTests: XCTestCase {
         XCTAssertEqual(result, [0, 1])
     }
     
-    @MainActor
     func test_that_reducer_should_be_able_to_assign_proxy_reduce() async throws {
         // Given
         var reducer = Reducer(CountIncreaseReduce(
@@ -170,7 +165,6 @@ final class ReducerTests: XCTestCase {
         XCTAssertEqual(result, [0, 10])
     }
     
-    @MainActor
     func test_that_initial_count_is_100_when_proxy_set_initial_count() async throws {
         // Given
         let reducer = Reducer<CountIncreaseReduce>(proxy: .init(
@@ -189,7 +183,6 @@ final class ReducerTests: XCTestCase {
         XCTAssertEqual(result, [100])
     }
     
-    @MainActor
     func test_that_count_increases_when_proxy_receiving_increase_action() async throws {
         // Given
         let reducer = Reducer<CountIncreaseReduce>(proxy: .init(
@@ -226,7 +219,6 @@ final class ReducerTests: XCTestCase {
         XCTAssertEqual(result, [0, 1])
     }
     
-    @MainActor
     func test_that_count_increases_10_when_proxy_receiving_increase_action() async throws {
         // Given
         let reducer = Reducer<CountIncreaseReduce>(proxy: .init(
@@ -264,7 +256,6 @@ final class ReducerTests: XCTestCase {
         XCTAssertEqual(result, [0, 10, 20])
     }
     
-    @MainActor
     func test_that_count_does_not_mutate_when_proxy_same_action_twice() async throws {
         // Given
         let reducer = Reducer<CountIncreaseReduce>(proxy: .init(
@@ -304,7 +295,6 @@ final class ReducerTests: XCTestCase {
         XCTAssertEqual(result, [0, 1])
     }
     
-    @MainActor
     func test_that_count_increases_when_proxy_mutate_in_start() async throws {
         // Given
         var cancellable: AnyCancellable? = nil
@@ -336,7 +326,6 @@ final class ReducerTests: XCTestCase {
         XCTAssertGreaterThan(result.last ?? 0, 0)
     }
     
-    @MainActor
     func test_that_reducer_can_assign_proxy_inherited_reduce() async throws {
         // Given
         let reducer = Reducer<CountIncreaseReduce>(
@@ -357,4 +346,22 @@ final class ReducerTests: XCTestCase {
         // Then
         XCTAssertEqual(result, [0, 10])
     }
+    
+    func test_that_count_increases_when_error_is_thrown_in_mutation() async throws {
+        // Given
+        let sut = Reducer(ErrorReduce())
+        
+        // When
+        Task {
+            sut.action(.occurError(TestError("increase count")))
+        }
+        
+        let result = try await wait(
+            sut.$state.map(\.count),
+            timeout: 1
+        )
+        
+        // Then
+        XCTAssertEqual(result, [0, 1])
+    }
 }