diff --git a/src/features/BeautificationManager.js b/src/features/BeautificationManager.js
index 9198879038..4908e458b8 100644
--- a/src/features/BeautificationManager.js
+++ b/src/features/BeautificationManager.js
@@ -323,6 +323,10 @@ define(function (require, exports, module) {
         if(!_isBeautifyOnSaveEnabled() || !editor || editor.document.file.fullPath !== doc.file.fullPath){
             return;
         }
+        if(!_getEnabledProviders(doc.file.fullPath).length){
+            // no beautify provider registered for this file type, silently skip instead of showing an error.
+            return;
+        }
         editor.clearSelection();
         _beautifyCommand();
     }
diff --git a/test/UnitTestSuite.js b/test/UnitTestSuite.js
index 3827d7ccd2..7e63d00eb8 100644
--- a/test/UnitTestSuite.js
+++ b/test/UnitTestSuite.js
@@ -110,6 +110,7 @@ define(function (require, exports, module) {
     require("spec/QuickViewManager-test");
     require("spec/SelectionViewManager-test");
     require("spec/BeautificationManager-test");
+    require("spec/Beautify-integ-test");
     require("spec/Template-for-integ-test");
     require("spec/LiveDevelopmentMultiBrowser-test");
     require("spec/LiveDevelopmentCustomServer-test");
diff --git a/test/spec/BeautificationManager-test.js b/test/spec/BeautificationManager-test.js
index 5b0898a4ca..acb9023595 100644
--- a/test/spec/BeautificationManager-test.js
+++ b/test/spec/BeautificationManager-test.js
@@ -74,6 +74,12 @@ define(function (require, exports, module) {
 
         afterEach(async function () {
             SpecRunnerUtils.destroyMockEditor(testDocument);
+            // safety net: a test that fails/times out partway through can leave "beautify on save"
+            // toggled on, which would otherwise leak into and break unrelated tests/suites.
+            let beautifyOnSaveCmd = CommandManager.get(Commands.EDIT_BEAUTIFY_CODE_ON_SAVE);
+            if(beautifyOnSaveCmd.getChecked()){
+                await awaitsForDone(CommandManager.execute(Commands.EDIT_BEAUTIFY_CODE_ON_SAVE), "beautify on save reset");
+            }
         });
 
         it("should register and unregister beautifier for all languages and beautifyText", async function () {
diff --git a/test/spec/Beautify-integ-test.js b/test/spec/Beautify-integ-test.js
new file mode 100644
index 0000000000..e5838b082b
--- /dev/null
+++ b/test/spec/Beautify-integ-test.js
@@ -0,0 +1,140 @@
+/*
+ * GNU AGPL-3.0 License
+ *
+ * Copyright (c) 2021 - present core.ai . All rights reserved.
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see https://opensource.org/licenses/AGPL-3.0.
+ *
+ */
+
+/*global describe, it, expect, beforeAll, afterAll, afterEach, awaitsFor, awaitsForDone, jsPromise */
+
+define(function (require, exports, module) {
+
+
+    const SpecRunnerUtils = require("spec/SpecRunnerUtils"),
+        Commands = require("command/Commands");
+
+    describe("integration: Beautify", function () {
+        let testWindow, $, brackets,
+            CommandManager, FileViewController, EditorManager, FileSystem,
+            BeautificationManager, testProjectPath;
+
+        // "csharp" is a real registered language with no beautify provider shipped in core/default
+        // extensions - see BeautificationManager-test.js for the same assumption.
+        const provider = {
+            beautifyTextProvider: function (textToBeautify) {
+                return Promise.resolve({originalText: textToBeautify, changedText: "beautified!"});
+            },
+            beautifyEditorProvider: function (editor) {
+                return Promise.resolve({originalText: editor.document.getText(), changedText: "beautified!"});
+            }
+        };
+
+        beforeAll(async function () {
+            // do not use force option in brackets core integration tests. Tests are assumed to reuse the existing
+            // test window instance for fast runs.
+            testWindow = await SpecRunnerUtils.createTestWindowAndRun();
+            brackets = testWindow.brackets;
+            $ = testWindow.$;
+            CommandManager = brackets.test.CommandManager;
+            FileViewController = brackets.test.FileViewController;
+            EditorManager = brackets.test.EditorManager;
+            FileSystem = brackets.test.FileSystem;
+            BeautificationManager = brackets.test.BeautificationManager;
+
+            testProjectPath = SpecRunnerUtils.getTempDirectory() + "/beautify-test";
+            await SpecRunnerUtils.createTempDirectory();
+            await SpecRunnerUtils.ensureExistsDirAsync(testProjectPath);
+            await jsPromise(SpecRunnerUtils.createTextFile(
+                testProjectPath + "/plain.txt", "hello world", FileSystem));
+            await jsPromise(SpecRunnerUtils.createTextFile(
+                testProjectPath + "/sample.cs", "original code", FileSystem));
+
+            await SpecRunnerUtils.loadProjectInTestWindow(testProjectPath);
+            BeautificationManager.registerBeautificationProvider(provider, ["csharp"]);
+        }, 30000);
+
+        afterAll(async function () {
+            // safety net: if the test that registers this provider fails/times out before reaching its
+            // own cleanup, or never runs at all, don't leak the registration past this suite.
+            try {
+                BeautificationManager.removeBeautificationProvider(provider, ["csharp"]);
+            } catch (e) {
+                // provider was never registered - nothing to clean up.
+            }
+            testWindow = null;
+            $ = null;
+            brackets = null;
+            CommandManager = null;
+            FileViewController = null;
+            EditorManager = null;
+            FileSystem = null;
+            BeautificationManager = null;
+            await SpecRunnerUtils.closeTestWindow();
+        }, 30000);
+
+        afterEach(async function () {
+            testWindow.brackets.test.MainViewManager._closeAll(testWindow.brackets.test.MainViewManager.ALL_PANES);
+            // safety net: a failing test could otherwise leave "beautify on save" toggled on and leak
+            // into other tests/suites.
+            let beautifyOnSaveCmd = CommandManager.get(Commands.EDIT_BEAUTIFY_CODE_ON_SAVE);
+            if(beautifyOnSaveCmd.getChecked()){
+                await awaitsForDone(CommandManager.execute(Commands.EDIT_BEAUTIFY_CODE_ON_SAVE), "beautify on save reset");
+            }
+        });
+
+        it("should not show an error popup saving a file type with no beautify provider (#3103)", async function () {
+            // regression test: https://github.com/phcode-dev/phoenix/issues/3103
+            // Saving a file whose type has no registered beautification provider (eg. plain text) with
+            // "beautify on save" enabled should silently be a no-op instead of showing an error popover.
+            await awaitsForDone(CommandManager.execute(Commands.EDIT_BEAUTIFY_CODE_ON_SAVE), "enable beautify on save");
+            await awaitsForDone(FileViewController.openAndSelectDocument(
+                testProjectPath + "/plain.txt", FileViewController.PROJECT_MANAGER), "open plain.txt");
+
+            let editor = EditorManager.getActiveEditor();
+            editor.document.replaceRange(" edited", editor.getEndingCursorPos());
+            await awaitsForDone(CommandManager.execute(Commands.FILE_SAVE), "save plain.txt");
+
+            // A regression here would only show up asynchronously (beautifyEditor's provider lookup
+            // rejects a couple of promise ticks after "documentSaved" fires), so drain the microtask
+            // queue a generous number of times before asserting nothing happened. This is a fixed
+            // number of microtask hops, not a wall-clock wait, so it can't be flaky.
+            for (let i = 0; i < 20; i++) {
+                await Promise.resolve();
+            }
+
+            expect($(".popover-message").length).toBe(0);
+            expect(editor.document.getText()).toBe("hello world edited");
+        });
+
+        it("should beautify on save when a provider is registered for the file type", async function () {
+            await awaitsForDone(CommandManager.execute(Commands.EDIT_BEAUTIFY_CODE_ON_SAVE), "enable beautify on save");
+            await awaitsForDone(FileViewController.openAndSelectDocument(
+                testProjectPath + "/sample.cs", FileViewController.PROJECT_MANAGER), "open sample.cs");
+
+            let editor = EditorManager.getActiveEditor();
+            expect(editor.document.getText()).toBe("original code");
+            // FILE_SAVE (and thus the "documentSaved" event beautify-on-save listens for) is a no-op
+            // unless the document is dirty, so make an edit first.
+            editor.document.replaceRange(" edited", editor.getEndingCursorPos());
+            await awaitsForDone(CommandManager.execute(Commands.FILE_SAVE), "save sample.cs");
+
+            await awaitsFor(function () {
+                return editor.document.getText() === "beautified!";
+            }, "waiting for beautify on save done", 5000);
+            expect(editor.document.getText()).toBe("beautified!");
+        });
+    });
+});