diff --git a/app/src/flux/mailsync-bridge.es6 b/app/src/flux/mailsync-bridge.es6
index ee909eea9..9c4bac79b 100644
--- a/app/src/flux/mailsync-bridge.es6
+++ b/app/src/flux/mailsync-bridge.es6
@@ -341,6 +341,7 @@ export default class MailsyncBridge {
     DatabaseStore.trigger(record);
 
     // Run task success / error handlers if the task is now complete
+    // Note: cannot use `record.objectClass` because of subclass names
     if (record.type === 'persist' && record.objects[0] instanceof Task) {
       for (const task of record.objects) {
         if (task.status !== 'complete') {
diff --git a/app/src/flux/stores/mail-rules-store.es6 b/app/src/flux/stores/mail-rules-store.es6
index e28030066..c40a81e45 100644
--- a/app/src/flux/stores/mail-rules-store.es6
+++ b/app/src/flux/stores/mail-rules-store.es6
@@ -11,13 +11,25 @@ import MailRulesProcessor from '../../mail-rules-processor';
 import { ConditionMode, ConditionTemplates, ActionTemplates } from '../../mail-rules-templates';
 
 const RulesJSONKey = 'MailRules-V2';
+const AutoSinceJSONKey = 'MailRules-Auto-Since';
 
 class MailRulesStore extends MailspringStore {
   constructor() {
     super();
 
+    /* This is a bit strange - if the user has mail rules enabled, they only
+    expect rules to be applied to "new" mail. Not "new" mail as in just created,
+    since that includes old mail we're syncing for the first time. Just "new"
+    mail that has arrived since they last ran Mailspring. So, we keep a date. */
+    this._autoSince = (window.localStorage.getItem(AutoSinceJSONKey) || 0) / 1;
+    if (this._autoSince === 0) {
+      window.localStorage.setItem(AutoSinceJSONKey, Date.now());
+      this._autoSince = Date.now();
+    }
+
     this._reprocessing = {};
     this._rules = [];
+
     try {
       const txt = window.localStorage.getItem(RulesJSONKey);
       if (txt) {
@@ -34,6 +46,8 @@ class MailRulesStore extends MailspringStore {
     this.listenTo(Actions.disableMailRule, this._onDisableMailRule);
     this.listenTo(Actions.startReprocessingMailRules, this._onStartReprocessing);
     this.listenTo(Actions.stopReprocessingMailRules, this._onStopReprocessing);
+
+    this.listenTo(DatabaseStore, this._onDatabaseChanged);
   }
 
   rules() {
@@ -52,6 +66,22 @@ class MailRulesStore extends MailspringStore {
     return this._reprocessing;
   }
 
+  _onDatabaseChanged = record => {
+    // If the record contains new emails, process mail rules immediately.
+    // This is necessary to avoid emails from bouncing through the inbox.
+    if (record.type === 'persist' && record.objectClass === Message.name) {
+      const newMessages = record.objects.filter(msg => {
+        if (msg.version !== 1) return false;
+        if (msg.draft) return false;
+        if (!msg.date || msg.date.valueOf() < this._autoSince) return false;
+        return true;
+      });
+      if (newMessages.length > 0) {
+        MailRulesProcessor.processMessages(newMessages);
+      }
+    }
+  };
+
   _onDeleteMailRule = id => {
     this._rules = this._rules.filter(f => f.id !== id);
     this._saveMailRules();
diff --git a/app/src/flux/tasks/change-starred-task.es6 b/app/src/flux/tasks/change-starred-task.es6
index b28d3154d..f019f1d60 100644
--- a/app/src/flux/tasks/change-starred-task.es6
+++ b/app/src/flux/tasks/change-starred-task.es6
@@ -13,16 +13,6 @@ export default class ChangeStarredTask extends ChangeMailTask {
     }),
   });
 
-  constructor(data = {}) {
-    if (data.threads) {
-      data.threads = data.threads.filter(t => t.starred !== data.starred);
-    }
-    if (data.messages) {
-      data.messages = data.messages.filter(m => m.starred !== data.starred);
-    }
-    super(data);
-  }
-
   label() {
     return this.starred ? 'Starring' : 'Unstarring';
   }
diff --git a/app/src/flux/tasks/change-unread-task.es6 b/app/src/flux/tasks/change-unread-task.es6
index 3f563b36b..085f7c9aa 100644
--- a/app/src/flux/tasks/change-unread-task.es6
+++ b/app/src/flux/tasks/change-unread-task.es6
@@ -13,16 +13,6 @@ export default class ChangeUnreadTask extends ChangeMailTask {
     }),
   });
 
-  constructor(data = {}) {
-    if (data.threads) {
-      data.threads = data.threads.filter(t => t.unread !== data.unread);
-    }
-    if (data.messages) {
-      data.messages = data.messages.filter(m => m.unread !== data.unread);
-    }
-    super(data);
-  }
-
   label() {
     return this.unread ? 'Marking as unread' : 'Marking as read';
   }
diff --git a/app/src/mail-rules-processor.es6 b/app/src/mail-rules-processor.es6
index fd45fdb39..dc8abc5c4 100644
--- a/app/src/mail-rules-processor.es6
+++ b/app/src/mail-rules-processor.es6
@@ -24,10 +24,7 @@ information about the current view. Maybe after the unified inbox refactor...
 */
 const MailRulesActions = {
   markAsImportant: async (message, thread) => {
-    const important = await DatabaseStore.findBy(Label, {
-      role: 'important',
-      accountId: thread.accountId,
-    });
+    const important = CategoryStore.getCategoryByRole(thread.accountId, 'important');
     if (!important) {
       throw new Error('Could not find `important` label');
     }
@@ -52,6 +49,9 @@ const MailRulesActions = {
   },
 
   markAsRead: (message, thread) => {
+    if (thread.unread === false) {
+      return null;
+    }
     return new ChangeUnreadTask({
       unread: false,
       threads: [thread],
@@ -60,6 +60,9 @@ const MailRulesActions = {
   },
 
   star: (message, thread) => {
+    if (thread.starred === true) {
+      return null;
+    }
     return new ChangeStarredTask({
       starred: true,
       threads: [thread],
@@ -71,8 +74,8 @@ const MailRulesActions = {
     if (!value) {
       throw new Error('A folder is required.');
     }
-    const folder = await DatabaseStore.findBy(Folder, { id: value, accountId: thread.accountId });
-    if (!folder) {
+    const folder = CategoryStore.byId(thread.accountId, value);
+    if (!folder || !(folder instanceof Folder)) {
       throw new Error('The folder could not be found.');
     }
     return new ChangeFolderTask({
@@ -86,8 +89,8 @@ const MailRulesActions = {
     if (!value) {
       throw new Error('A label is required.');
     }
-    const label = await DatabaseStore.findBy(Label, { id: value, accountId: thread.accountId });
-    if (!label) {
+    const label = CategoryStore.byId(thread.accountId, value);
+    if (!label || !(label instanceof Label)) {
       throw new Error('The label could not be found.');
     }
     return new ChangeLabelsTask({
@@ -112,12 +115,11 @@ const MailRulesActions = {
       throw new Error('A label is required.');
     }
 
-    const { withId, withRole } = await Promise.props({
-      withId: DatabaseStore.findBy(Label, { id: roleOrId, accountId: thread.accountId }),
-      withRole: DatabaseStore.findBy(Label, { role: roleOrId, accountId: thread.accountId }),
-    });
-    const label = withId || withRole;
-    if (!label) {
+    const label = CategoryStore.categories(thread.accountId).find(
+      c => c.id === roleOrId || c.role === roleOrId
+    );
+
+    if (!label || !(label instanceof Label)) {
       throw new Error('The label could not be found.');
     }
     return new ChangeLabelsTask({
@@ -189,6 +191,12 @@ class MailRulesProcessor {
 
       const actionResults = await Promise.all(actionPromises);
       const actionTasks = actionResults.filter(r => r instanceof Task);
+
+      // mark that none of these tasks are undoable
+      actionTasks.forEach(t => {
+        t.canBeUndone = false;
+      });
+
       const performLocalPromises = actionTasks.map(t => TaskQueue.waitForPerformLocal(t));
       Actions.queueTasks(actionTasks);
       await performLocalPromises;