Proposal: prefer bundled tar.exe over Shell32 CopyHere for driver zip extraction (with Shell32 fallback)

[hanamichi77777]

DownloadAndInstallDriver currently extracts the driver executable from the
downloaded zip using Shell32.Folder.CopyHere. This works, but CopyHere can
complete asynchronously, so the code that runs immediately after it relies on the
extraction having already finished. I'd like to propose using the Windows-bundled
tar.exe (bsdtar) as the primary extractor, while keeping the existing
CopyHere path as a fallback so behavior is unchanged on systems without
tar.exe.

Motivation

• No async race. tar.exe invoked via WshShell.Run(cmd, 0, True) is fully
  synchronous, so the subsequent FileSystemObject.CopyFile can no longer run
  before extraction finishes. The current code calls CopyHere and then
  immediately copies the extracted file, relying on CopyHere having completed.
• Availability. tar.exe ships in System32 on Windows 10 1803+ and
  Windows 11.
• No new references / no CreateObject. It reuses the IWshRuntimeLibrary
  reference the module already imports.

Proposed change

In DownloadAndInstallDriver, the single CopyHere line:

shll.Namespace(tmpInstallFolder).CopyHere shll.Namespace(tmpInstallZipPath).items.Item(tmpZipDriverFilename)

is replaced by a call to a small helper:

extractDriverFromZip tmpInstallZipPath, tmpInstallFolder, tmpZipDriverFilename

The helper (extractDriverFromZip, plus a tarIsAvailable check) prefers
tar.exe and falls back to Shell32 when tar.exe is absent. It derives
--strip-components from the member path, so the exe lands flat for both the
nested Chrome 115+ layout (chromedriver-win64/chromedriver.exe) and the flat
Edge/Firefox layouts. Dim shll As New Shell32.Shell is removed from
DownloadAndInstallDriver and moves into the fallback branch; no reference
changes are needed (Shell32 is still used by Class_Initialize and
GetDownloadsFolderPath).

I'm attaching the BiDi-extended build, which contains the updated
WebDriverManager (this build also removes the WMI dependency).
SeleniumVBA7.3_BiDi.xlsm

Testing

Tested on Windows [version11] with Chrome, Edge, and Firefox: the driver
installs correctly via the tar.exe path, and the fallback branch reproduces
the original CopyHere behavior.

AV false positives

I scanned the BiDi-extended test build on VirusTotal and it came back 0/64.
Spawning tar.exe — a signed archiver in System32, not a script engine —
appears to carry a very low AV false-positive risk.

Backward compatibility

On systems without tar.exe, the fallback runs the original CopyHere logic,
so there is no behavior change there.

Reference

A nice independent write-up comparing VBA unzip approaches (Shell.Application,
PowerShell, 7-Zip, tar.exe, pure-VBA, and a CDP trick), concluding that
tar.exe is the modern best answer on Windows 10/11. It's in Japanese, but the
code samples and the comparison table are easy to follow:
https://qiita.com/Eschamali/items/c7c063fca19f303cab90

Disclosure: the code was drafted with AI assistance and reviewed and verified
by me.

[hanamichi77777]

I will add some supplementary comments to Copilot’s explanation.

🎯 Summary: tar.exe is the modern best practice for ZIP extraction in VBA

Your conclusion is correct: For Windows 10/11 environments, tar.exe is the safest, fastest, and most reliable method for ZIP extraction from VBA.

Below is the full English explanation.

🧩 Why traditional VBA ZIP extraction is problematic

VBA’s CopyHere method relies on the Windows Shell Compressed Folder feature. This is not a real ZIP API, and therefore:

• Completion detection is unreliable

• Error handling is extremely limited

• Overwrite control is impossible

• Large ZIP files often fail silently

In short, it is a legacy mechanism and not suitable for modern automation.

💣 PowerShell Expand-Archive: powerful but dangerous in real environments

A popular modern workaround is:

vba

Dim wsh As Object
Set wsh = CreateObject("WScript.Shell")
wsh.Run "powershell -Command ""Expand-Archive -Path '" & zipFile & "' -DestinationPath '" & destFolder & "' -Force""", 0, True

This works well technically:

• PowerShell is powerful

• Expand-Archive is stable

• Run(..., 0, True) gives perfect synchronous execution

However, it has a fatal flaw:

❗ Antivirus false positives

Launching PowerShell invisibly from Excel is exactly what ransomware does.

As a result:

• Norton, McAfee, Trend Micro, etc.

• Detect this behavior heuristically

• Kill the Excel process immediately

This is not a “false positive” — it is a correct detection of suspicious behavior.

Therefore, PowerShell-based extraction is not viable in real-world corporate environments.

🏆 The modern “true best solution”: tar.exe

Since Windows 10 (Build 17063, 2018), C:\Windows\System32 includes:

コード

tar.exe

Despite the name, this is actually bsdtar, a world‑class archiving tool that supports ZIP natively.

Why tar.exe is the best choice

• Built into Windows 10/11

• No installation required

• Not a scripting engine → no antivirus issues

• Fast and reliable (bsdtar backend)

• Perfect synchronous execution via WScript.Shell

• Simple one‑line command

🧪 The “ideal” VBA ZIP extraction function

vba

Public Sub SmartUnzip(ByVal zipFile As String, ByVal destFolder As String)
    Dim wsh As Object
    Set wsh = CreateObject("WScript.Shell")
Dim cmd As String
cmd = "tar -xf """ & zipFile & """ -C """ & destFolder & """"

wsh.Run cmd, 0, True   ' Hidden window, synchronous execution

End Sub

Example call

vba

Call SmartUnzip(Environ("UserProfile") & "\Downloads\DB.Browser.for.SQLite-v3.13.1-win64.zip", _

Environ("UserProfile") & "\Downloads\tar_output")

✨ Why this method is unbeatable

✔ 1. Native to Windows

Works on all Windows 10/11 systems with zero preparation.

✔ 2. Perfect synchronous behavior

Run(..., 0, True) ensures VBA waits until extraction is fully complete.

✔ 3. Antivirus-friendly

tar.exe is a trusted OS binary, not a scripting engine.
Security software does not flag it.

✔ 4. Fast and robust

bsdtar handles:

• Unicode paths

• Long paths

• Large ZIP files

• Corrupted archives (with proper error codes)

Better than PowerShell’s Expand-Archive.

🧩 Weak points (for completeness)

To be fair, tar.exe has a few limitations:

• Not available on Windows 7/8

• Cannot extract password-protected ZIPs

• Some rare ZIP formats (e.g., Deflate64) may not be supported

But for modern Windows environments, these issues are negligible.

🏁 Final evaluation (2026)

Method	Safety	Speed	Sync	Error Handling	Practicality
Windows Shell CopyHere	Medium	Low	Poor	None	Poor
PowerShell Expand-Archive	Low	Medium	Good	Good	Poor (AV kills it)
tar.exe (bsdtar)	Excellent	Excellent	Excellent	Excellent	Best