diff --git a/packages/cli/lib/commands/upgrade.ts b/packages/cli/lib/commands/upgrade.ts
index 1a8551b84..e1166156e 100644
--- a/packages/cli/lib/commands/upgrade.ts
+++ b/packages/cli/lib/commands/upgrade.ts
@@ -1,4 +1,4 @@
-import { GoogleAnalytics, ProjectConfig, Util } from "@igniteui/cli-core";
+import { GoogleAnalytics, ProjectConfig, type ProjectTemplate, Util } from "@igniteui/cli-core";
 import { PositionalArgs, UpgradeCommandType } from "./types";
 import { ArgumentsCamelCase } from "yargs";
 
@@ -38,7 +38,7 @@ const command: UpgradeCommandType = {
 			case "webcomponents":
 				if (projectType === "igx-ts" || projectType === "igr-ts" || projectType === "igc-ts") {
 					const projectLibrary = command.templateManager.getProjectLibrary(framework, projectType);
-					let project;
+					let project: ProjectTemplate;
 					if (!config.project.projectTemplate || !projectLibrary.hasProject(config.project.projectTemplate)) {
 						// in case project template is missing from the config we provide backward.
 						project = projectLibrary.getProject(projectLibrary.projectIds[0]);
diff --git a/packages/core/util/FileSystem.ts b/packages/core/util/FileSystem.ts
index 5457b1b17..ddce66d24 100644
--- a/packages/core/util/FileSystem.ts
+++ b/packages/core/util/FileSystem.ts
@@ -2,7 +2,7 @@
 import * as fs from "fs";
 import * as glob from "glob";
 import * as path from "path";
-import { IFileSystem } from "../types/FileSystem";
+import type { IFileSystem } from "../types/FileSystem";
 
 export class FsFileSystem implements IFileSystem {
 	public fileExists(filePath: string): boolean {
@@ -30,7 +30,8 @@ export class FsFileSystem implements IFileSystem {
 	}
 
 	public glob(dirPath: string, pattern: string): string[] {
-		return glob.sync(path.join(dirPath, pattern), { nodir: true })
-			.map(filePath => filePath.replace(/\\/g, "/"));
+		// NB!: glob 8+ patterns use `\` as escape only, so ensure posix-style:
+		const globPattern = path.join(dirPath, pattern).replace(/\\/g, "/");
+		return glob.sync(globPattern, { nodir: true });
 	}
 }
diff --git a/spec/unit/FsFileSystem-spec.ts b/spec/unit/FsFileSystem-spec.ts
new file mode 100644
index 000000000..a9c991031
--- /dev/null
+++ b/spec/unit/FsFileSystem-spec.ts
@@ -0,0 +1,43 @@
+import * as glob from "glob";
+import { FsFileSystem } from "../../packages/core/util/FileSystem";
+
+describe("Unit - FsFileSystem", () => {
+	let fileSystem: FsFileSystem;
+
+	beforeEach(() => {
+		fileSystem = new FsFileSystem();
+	});
+
+	describe("glob", () => {
+		it("should pass a forward-slash pattern to glob even when dirPath uses backslashes", () => {
+			spyOn(glob, "sync").and.returnValue([]);
+			const windowsDirPath = "C:\\Work\\git\\project\\src";
+			fileSystem.glob(windowsDirPath, "**/*.ts");
+			expect(glob.sync).toHaveBeenCalledWith(
+				"C:/Work/git/project/src/**/*.ts",
+				jasmine.objectContaining({ nodir: true })
+			);
+		});
+
+		it("should pass a forward-slash pattern to glob even when pattern contains backslashes", () => {
+			spyOn(glob, "sync").and.returnValue([]);
+			fileSystem.glob("C:\\Work\\project", "sub\\**\\*.ts");
+			expect(glob.sync).toHaveBeenCalledWith(
+				"C:/Work/project/sub/**/*.ts",
+				jasmine.objectContaining({ nodir: true })
+			);
+		});
+
+		it("should work correctly with forward-slash paths (non-Windows)", () => {
+			spyOn(glob, "sync").and.returnValue([
+				"/home/user/project/src/app.ts"
+			] as any);
+			const result = fileSystem.glob("/home/user/project", "src/**/*.ts");
+			expect(glob.sync).toHaveBeenCalledWith(
+				"/home/user/project/src/**/*.ts",
+				jasmine.objectContaining({ nodir: true })
+			);
+			expect(result).toEqual(["/home/user/project/src/app.ts"]);
+		});
+	});
+});