diff --git a/src/containers/gui.jsx b/src/containers/gui.jsx
index 2d74e21c2428bed32fd42da05ae2a6a4450207bb..2076286e3b315cdd36197b8d79343aa1ea5b40bc 100644
--- a/src/containers/gui.jsx
+++ b/src/containers/gui.jsx
@@ -66,12 +66,12 @@ class GUI extends React.Component {
     render () {
         if (this.props.isError) {
             throw new Error(
-                `Failed to load project from server [id=${window.location.hash}]: ${this.props.errStr}`);
+                `Failed to load project from server [id=${window.location.hash}]: ${this.props.errorMessage}`);
         }
         const {
             /* eslint-disable no-unused-vars */
             assetHost,
-            errStr,
+            errorMessage,
             hideIntro,
             isError,
             isShowingProject,
@@ -101,12 +101,12 @@ class GUI extends React.Component {
 GUI.propTypes = {
     assetHost: PropTypes.string,
     children: PropTypes.node,
-    errStr: PropTypes.string,
+    errorMessage: PropTypes.string,
     fetchingProject: PropTypes.bool,
     hideIntro: PropTypes.bool,
     importInfoVisible: PropTypes.bool,
-    isError: PropTypes.bool,
     intl: intlShape,
+    isError: PropTypes.bool,
     isLoading: PropTypes.bool,
     isShowingProject: PropTypes.bool,
     loadingStateVisible: PropTypes.bool,
@@ -136,7 +136,7 @@ const mapStateToProps = (state, ownProps) => {
         cardsVisible: state.scratchGui.cards.visible,
         costumeLibraryVisible: state.scratchGui.modals.costumeLibrary,
         costumesTabVisible: state.scratchGui.editorTab.activeTabIndex === COSTUMES_TAB_INDEX,
-        errStr: state.scratchGui.projectState.errStr,
+        errorMessage: state.scratchGui.projectState.errorMessage,
         importInfoVisible: state.scratchGui.modals.importInfo,
         isError: getIsError(loadingState),
         isPlayerOnly: state.scratchGui.mode.isPlayerOnly,
diff --git a/src/lib/project-fetcher-hoc.jsx b/src/lib/project-fetcher-hoc.jsx
index 20fb80602e771d7223aa533079b955d25661b3ea..1a8322a071c214088249e5cad4b4137c5f3bcc94 100644
--- a/src/lib/project-fetcher-hoc.jsx
+++ b/src/lib/project-fetcher-hoc.jsx
@@ -126,7 +126,7 @@ const ProjectFetcherHOC = function (WrappedComponent) {
         reduxProjectId: state.scratchGui.projectState.projectId
     });
     const mapDispatchToProps = dispatch => ({
-        onError: errStr => dispatch(onError(errStr)),
+        onError: errorMessage => dispatch(onError(errorMessage)),
         onFetchedProjectData: (projectData, loadingState) =>
             dispatch(onFetchedProjectData(projectData, loadingState)),
         setProjectId: projectId => dispatch(setProjectId(projectId))
diff --git a/src/lib/project-saver-hoc.jsx b/src/lib/project-saver-hoc.jsx
index 5bc15f1d5b6fe2b40afc9fe45e909d1471d15cd2..6d85eca4c005603c3848045d79419b6a8fa3ea35 100644
--- a/src/lib/project-saver-hoc.jsx
+++ b/src/lib/project-saver-hoc.jsx
@@ -141,7 +141,7 @@ const ProjectSaverHOC = function (WrappedComponent) {
         createProject: () => dispatch(createProject()),
         onCreated: projectId => dispatch(onCreated(projectId)),
         onUpdated: (projectId, loadingState) => dispatch(onUpdated(projectId, loadingState)),
-        onError: errStr => dispatch(onError(errStr)),
+        onError: errorMessage => dispatch(onError(errorMessage)),
         saveProject: () => dispatch(saveProject())
     });
     // Allow incoming props to override redux-provided props. Used to mock in tests.
diff --git a/src/lib/vm-manager-hoc.jsx b/src/lib/vm-manager-hoc.jsx
index 20271706d4a584b5a34f598dd267726bab3e410c..6e1d0125cf04f10e35484aebebfebf4f569c2e2a 100644
--- a/src/lib/vm-manager-hoc.jsx
+++ b/src/lib/vm-manager-hoc.jsx
@@ -97,7 +97,7 @@ const vmManagerHOC = function (WrappedComponent) {
     };
 
     const mapDispatchToProps = dispatch => ({
-        onError: errStr => dispatch(onError(errStr)),
+        onError: errorMessage => dispatch(onError(errorMessage)),
         onLoadedProject: (loadingState, canSave) =>
             dispatch(onLoadedProject(loadingState, canSave))
     });
diff --git a/src/reducers/project-state.js b/src/reducers/project-state.js
index 1b80fd3e481ce92c6b55124273489dc92f7df41d..9ade631624b676b90721edc15ef0403e4f3e0e57 100644
--- a/src/reducers/project-state.js
+++ b/src/reducers/project-state.js
@@ -70,7 +70,7 @@ const getIsError = loadingState => (
 );
 
 const initialState = {
-    errStr: null,
+    errorMessage: null,
     projectData: null,
     projectId: null,
     loadingState: LoadingState.NOT_LOADED
@@ -224,7 +224,7 @@ const reducer = function (state, action) {
         ].includes(state.loadingState)) {
             return Object.assign({}, state, {
                 loadingState: LoadingState.ERROR,
-                errStr: action.errStr
+                errorMessage: action.errorMessage
             });
         }
         return state;
@@ -298,9 +298,9 @@ const onUpdated = loadingState => {
     }
 };
 
-const onError = errStr => ({
+const onError = errorMessage => ({
     type: GO_TO_ERROR_STATE,
-    errStr: errStr
+    errorMessage: errorMessage
 });
 
 const setProjectId = id => ({
diff --git a/test/unit/reducers/project-state-reducer.test.js b/test/unit/reducers/project-state-reducer.test.js
index c91d1909cca70344c3e5ae6d4db3680cd8fefdcc..81f2d2c0c96611c2b0c54a49a6ebf7e627f06eb1 100644
--- a/test/unit/reducers/project-state-reducer.test.js
+++ b/test/unit/reducers/project-state-reducer.test.js
@@ -17,7 +17,7 @@ test('initialState', () => {
     let defaultState;
     /* projectStateReducer(state, action) */
     expect(projectStateReducer(defaultState, {type: 'anything'})).toBeDefined();
-    expect(projectStateReducer(defaultState, {type: 'anything'}).errStr).toBe(null);
+    expect(projectStateReducer(defaultState, {type: 'anything'}).errorMessage).toBe(null);
     expect(projectStateReducer(defaultState, {type: 'anything'}).projectData).toBe(null);
     expect(projectStateReducer(defaultState, {type: 'anything'}).projectId).toBe(null);
     expect(projectStateReducer(defaultState, {type: 'anything'}).loadingState).toBe(LoadingState.NOT_LOADED);
@@ -229,23 +229,23 @@ test('onError from various states should show error', () => {
     ];
     for (const startState of startStates) {
         const initialState = {
-            errStr: null,
+            errorMessage: null,
             loadingState: startState
         };
         const action = onError('Error string');
         const resultState = projectStateReducer(initialState, action);
         expect(resultState.loadingState).toBe(LoadingState.ERROR);
-        expect(resultState.errStr).toBe('Error string');
+        expect(resultState.errorMessage).toBe('Error string');
     }
 });
 
 test('onError from showing project should show error', () => {
     const initialState = {
-        errStr: null,
+        errorMessage: null,
         loadingState: LoadingState.FETCHING_WITH_ID
     };
     const action = onError('Error string');
     const resultState = projectStateReducer(initialState, action);
     expect(resultState.loadingState).toBe(LoadingState.ERROR);
-    expect(resultState.errStr).toBe('Error string');
+    expect(resultState.errorMessage).toBe('Error string');
 });