diff --git a/lib/controllers/prepare-controller.ts b/lib/controllers/prepare-controller.ts
index 5d687cd933..cbf234616a 100644
--- a/lib/controllers/prepare-controller.ts
+++ b/lib/controllers/prepare-controller.ts
@@ -143,7 +143,10 @@ export class PrepareController
 		prepareData: IPrepareData,
 		projectData: IProjectData,
 	): Promise<IPrepareResultData> {
-		await this.$projectService.ensureAppResourcesExist(projectData.projectDir);
+		await this.$projectService.ensureAppResourcesExist(
+			projectData.projectDir,
+			this.$mobileHelper.normalizePlatformName(prepareData.platform),
+		);
 		await this.$platformController.addPlatformIfNeeded(
 			prepareData,
 			projectData,
diff --git a/lib/definitions/project.d.ts b/lib/definitions/project.d.ts
index 67f1a8b087..d013d42b07 100644
--- a/lib/definitions/project.d.ts
+++ b/lib/definitions/project.d.ts
@@ -95,8 +95,12 @@ interface IProjectService {
 	 * Checks if App_Resources exists, or pulls down a fresh set
 	 * from the default template otherwise.
 	 * @param {string} projectDir
+	 * @param {string} platformDirName When set, also adds App_Resources/<platformDirName> from the default template if it is missing.
 	 */
-	ensureAppResourcesExist(projectDir: string): Promise<void>;
+	ensureAppResourcesExist(
+		projectDir: string,
+		platformDirName?: string,
+	): Promise<void>;
 }
 
 interface INsConfigPlaform {
diff --git a/lib/services/project-service.ts b/lib/services/project-service.ts
index 91bc4bce84..0ab29c55c8 100644
--- a/lib/services/project-service.ts
+++ b/lib/services/project-service.ts
@@ -224,7 +224,10 @@ export class ProjectService implements IProjectService {
 	}
 
 	@performanceLog()
-	public async ensureAppResourcesExist(projectDir: string): Promise<void> {
+	public async ensureAppResourcesExist(
+		projectDir: string,
+		platformDirName?: string
+	): Promise<void> {
 		const projectData = this.$projectDataService.getProjectData(projectDir);
 		const appResourcesDestinationPath = projectData.getAppResourcesDirectoryPath(
 			projectDir
@@ -235,23 +238,48 @@ export class ProjectService implements IProjectService {
 				"Project does not have App_Resources - fetching from default template."
 			);
 			this.$fs.createDirectory(appResourcesDestinationPath);
-			const tempDir = await this.$tempService.mkdirSync("ns-default-template");
 			// the template installed doesn't have App_Resources -> get from a default template
-			await this.$pacoteService.extractPackage(
-				constants.RESERVED_TEMPLATE_NAMES["default"],
-				tempDir
-			);
-			const templateProjectData = this.$projectDataService.getProjectData(
-				tempDir
-			);
-			const templateAppResourcesDir = templateProjectData.getAppResourcesDirectoryPath(
-				tempDir
-			);
+			const templateAppResourcesDir = await this.getDefaultTemplateAppResourcesDir();
 			this.$fs.copyFile(
 				path.join(templateAppResourcesDir, "*"),
 				appResourcesDestinationPath
 			);
+			return;
 		}
+
+		// An app created before a platform was supported (e.g. Windows) has no folder for it.
+		if (
+			platformDirName &&
+			!this.$fs.exists(path.join(appResourcesDestinationPath, platformDirName))
+		) {
+			const templateAppResourcesDir = await this.getDefaultTemplateAppResourcesDir();
+			const templatePlatformDir = path.join(
+				templateAppResourcesDir,
+				platformDirName
+			);
+			if (!this.$fs.exists(templatePlatformDir)) {
+				this.$logger.warn(
+					`App_Resources/${platformDirName} is missing and the default template does not provide one.`
+				);
+				return;
+			}
+			this.$logger.info(
+				`Adding App_Resources/${platformDirName} from the default template.`
+			);
+			this.$fs.copyFile(templatePlatformDir, appResourcesDestinationPath);
+		}
+	}
+
+	private async getDefaultTemplateAppResourcesDir(): Promise<string> {
+		const tempDir = await this.$tempService.mkdirSync("ns-default-template");
+		await this.$pacoteService.extractPackage(
+			constants.RESERVED_TEMPLATE_NAMES["default"],
+			tempDir
+		);
+		const templateProjectData = this.$projectDataService.getProjectData(
+			tempDir
+		);
+		return templateProjectData.getAppResourcesDirectoryPath(tempDir);
 	}
 
 	@performanceLog()
diff --git a/test/project-service.ts b/test/project-service.ts
index 21d1e5f1dc..dadc3349ad 100644
--- a/test/project-service.ts
+++ b/test/project-service.ts
@@ -342,4 +342,99 @@ describe("projectService", () => {
 			assert.isFalse(projectService.isValidNativeScriptProject("some-dir"));
 		});
 	});
+
+	describe("ensureAppResourcesExist", () => {
+		const projectDir = path.resolve("app-resources-project");
+		const appResources = path.join(projectDir, "App_Resources");
+		const templateDir = path.resolve("default-template");
+		const templateAppResources = path.join(templateDir, "App_Resources");
+
+		const setup = (existing: string[]) => {
+			const exists = new Set(existing.map((p) => path.resolve(p)));
+			const copies: { from: string; to: string }[] = [];
+			let extracted = 0;
+			const testInjector = new yok.Yok();
+			testInjector.register("fs", {
+				exists: (p: string) => exists.has(path.resolve(p)),
+				createDirectory: (p: string) => exists.add(path.resolve(p)),
+				copyFile: (from: string, to: string) => copies.push({ from, to }),
+			});
+			testInjector.register("logger", LoggerStub);
+			testInjector.register("projectDataService", {
+				getProjectData: (dir: string): IProjectData =>
+					<any>{
+						getAppResourcesDirectoryPath: (d: string) =>
+							path.join(d === templateDir ? templateDir : dir, "App_Resources"),
+					},
+			});
+			testInjector.register("pacoteService", {
+				extractPackage: async () => {
+					extracted++;
+				},
+			});
+			testInjector.register("tempService", {
+				mkdirSync: async () => templateDir,
+			});
+			for (const name of [
+				"options",
+				"hooksService",
+				"packageManager",
+				"errors",
+				"projectConfigService",
+				"projectHelper",
+				"projectNameService",
+				"projectTemplatesService",
+				"staticConfig",
+				"childProcess",
+			]) {
+				testInjector.register(name, {});
+			}
+			const projectService: IProjectService = testInjector.resolve(
+				ProjectServiceLib.ProjectService
+			);
+			return { projectService, copies, extracted: () => extracted };
+		};
+
+		it("copies the whole App_Resources when it is missing", async () => {
+			const { projectService, copies } = setup([]);
+			await projectService.ensureAppResourcesExist(projectDir, "Windows");
+			assert.deepEqual(copies, [
+				{ from: path.join(templateAppResources, "*"), to: appResources },
+			]);
+		});
+
+		it("adds a missing platform folder from the default template", async () => {
+			const { projectService, copies } = setup([
+				appResources,
+				path.join(templateAppResources, "Windows"),
+			]);
+			await projectService.ensureAppResourcesExist(projectDir, "Windows");
+			assert.deepEqual(copies, [
+				{ from: path.join(templateAppResources, "Windows"), to: appResources },
+			]);
+		});
+
+		it("leaves an existing platform folder alone", async () => {
+			const { projectService, copies, extracted } = setup([
+				appResources,
+				path.join(appResources, "Windows"),
+			]);
+			await projectService.ensureAppResourcesExist(projectDir, "Windows");
+			assert.deepEqual(copies, []);
+			assert.equal(extracted(), 0);
+		});
+
+		it("copies nothing when the template has no folder for the platform", async () => {
+			const { projectService, copies } = setup([appResources]);
+			await projectService.ensureAppResourcesExist(projectDir, "Windows");
+			assert.deepEqual(copies, []);
+		});
+
+		it("does not look at platform folders without a platform", async () => {
+			const { projectService, copies, extracted } = setup([appResources]);
+			await projectService.ensureAppResourcesExist(projectDir);
+			assert.deepEqual(copies, []);
+			assert.equal(extracted(), 0);
+		});
+	});
 });