diff --git a/cli/src/update_service.rs b/cli/src/update_service.rs
index 4bec13d6e86a3..cc3caeb446924 100644
--- a/cli/src/update_service.rs
+++ b/cli/src/update_service.rs
@@ -3,7 +3,7 @@
  *  Licensed under the MIT License. See License.txt in the project root for license information.
  *--------------------------------------------------------------------------------------------*/
 
-use std::{ffi::OsStr, fmt, path::Path};
+use std::{fmt, path::Path};
 
 use serde::{Deserialize, Serialize};
 
@@ -11,10 +11,11 @@ use crate::{
 	constants::VSCODE_CLI_UPDATE_ENDPOINT,
 	debug, log, options, spanf,
 	util::{
-		errors::{AnyError, CodeError, WrappedError},
+		errors::{wrap, AnyError, CodeError, WrappedError},
 		http::{BoxedHttp, SimpleResponse},
 		io::ReportCopyProgress,
-		tar, zipper,
+		tar::{self, has_gzip_header},
+		zipper,
 	},
 };
 
@@ -178,10 +179,10 @@ pub fn unzip_downloaded_release<T>(
 where
 	T: ReportCopyProgress,
 {
-	if compressed_file.extension() == Some(OsStr::new("zip")) {
-		zipper::unzip_file(compressed_file, target_dir, reporter)
-	} else {
-		tar::decompress_tarball(compressed_file, target_dir, reporter)
+	match has_gzip_header(compressed_file) {
+		Ok((f, true)) => tar::decompress_tarball(f, target_dir, reporter),
+		Ok((f, false)) => zipper::unzip_file(f, target_dir, reporter),
+		Err(e) => Err(wrap(e, "error checking for gzip header")),
 	}
 }
 
diff --git a/cli/src/util/tar.rs b/cli/src/util/tar.rs
index fe4d426970021..10577140325eb 100644
--- a/cli/src/util/tar.rs
+++ b/cli/src/util/tar.rs
@@ -5,8 +5,8 @@
 use crate::util::errors::{wrap, WrappedError};
 
 use flate2::read::GzDecoder;
-use std::fs;
-use std::io::Seek;
+use std::fs::{self, File};
+use std::io::{Read, Seek};
 use std::path::{Path, PathBuf};
 use tar::Archive;
 
@@ -57,16 +57,13 @@ fn should_skip_first_segment(file: &fs::File) -> Result<(bool, u64), WrappedErro
 }
 
 pub fn decompress_tarball<T>(
-	path: &Path,
+	mut tar_gz: File,
 	parent_path: &Path,
 	mut reporter: T,
 ) -> Result<(), WrappedError>
 where
 	T: ReportCopyProgress,
 {
-	let mut tar_gz = fs::File::open(path)
-		.map_err(|e| wrap(e, format!("error opening file {}", path.display())))?;
-
 	let (skip_first, num_entries) = should_skip_first_segment(&tar_gz)?;
 	let report_progress_every = num_entries / 20;
 	let mut entries_so_far = 0;
@@ -81,7 +78,7 @@ where
 	let mut archive = Archive::new(tar);
 	archive
 		.entries()
-		.map_err(|e| wrap(e, format!("error opening archive {}", path.display())))?
+		.map_err(|e| wrap(e, "error opening archive"))?
 		.filter_map(|e| e.ok())
 		.try_for_each::<_, Result<_, WrappedError>>(|mut entry| {
 			// approximate progress based on where we are in the archive:
@@ -118,3 +115,13 @@ where
 
 	Ok(())
 }
+
+pub fn has_gzip_header(path: &Path) -> std::io::Result<(File, bool)> {
+	let mut file = fs::File::open(path)?;
+	let mut header = [0; 2];
+	let _ = file.read_exact(&mut header);
+
+	file.rewind()?;
+
+	Ok((file, header[0] == 0x1f && header[1] == 0x8b))
+}
diff --git a/cli/src/util/zipper.rs b/cli/src/util/zipper.rs
index 69bcf2d23f6d3..5521fa42c5424 100644
--- a/cli/src/util/zipper.rs
+++ b/cli/src/util/zipper.rs
@@ -44,15 +44,12 @@ fn should_skip_first_segment(archive: &mut ZipArchive<File>) -> bool {
 	archive.len() > 1 // prefix removal is invalid if there's only a single file
 }
 
-pub fn unzip_file<T>(path: &Path, parent_path: &Path, mut reporter: T) -> Result<(), WrappedError>
+pub fn unzip_file<T>(file: File, parent_path: &Path, mut reporter: T) -> Result<(), WrappedError>
 where
 	T: ReportCopyProgress,
 {
-	let file = fs::File::open(path)
-		.map_err(|e| wrap(e, format!("unable to open file {}", path.display())))?;
-
-	let mut archive = zip::ZipArchive::new(file)
-		.map_err(|e| wrap(e, format!("failed to open zip archive {}", path.display())))?;
+	let mut archive =
+		zip::ZipArchive::new(file).map_err(|e| wrap(e, "failed to open zip archive"))?;
 
 	let skip_segments_no = usize::from(should_skip_first_segment(&mut archive));
 	let report_progress_every = archive.len() / 20;