Windows Explorer Instability Caused by Video CDs

There is a peculiar glitch within the Windows ecosystem specifically triggered by Video CDs (VCDs). While VCDs are largely relics of the past, interacting with them in a specific way can effectively paralyze the operating system's shell.

🛠️ How to Reproduce the Glitch

If you wish to test this, you will need a VCD. If you lack physical media, you can download a .bin+cue image and burn it using a tool like AnyBurn.

• Insert the Video CD into the drive.
• Launch Windows Explorer.
• Attempt to copy the disc contents (specifically the MPEGAV folder containing the large media files) to your local hard drive.

📉 The Failure State

During the transfer, the copying speed will suddenly plummet. Mathematically, the transfer rate behaves as: $\lim_{t \to \text{crash}} \text{speed} = 0 \text{ MB/s}$

Once the speed hits zero, Windows Explorer enters a "broken" state. Even if you cancel the operation and eject the disc, the system remains unstable:

• UI Glitches: Various elements of the Windows interface begin to malfunction.
• Refresh Issues: New files or folders created on the system are $\text{invisible}$ unless the user manually refreshes the view.
• Process Lock: The explorer.exe process cannot be restarted.

Warning: A standard "soft" restart via the Start Menu is ineffective. The system will typically hang indefinitely on the "Restarting" screen. A hard hardware reset is the only viable solution.

🔍 Technical Investigation

To analyze this without constantly crashing a primary machine, the author utilized VMware Workstation, allowing for isolated reboots.

Version Compatibility

The bug is not present in base installations of Windows 10 or Windows 11 22H2. It was introduced in the following updates:

Trigger Analysis

The bug is most consistent with physical media, though virtual drives (via Alcohol 120%) can also trigger it.

What does NOT trigger the bug:

• Playing the disc via Windows Media Player.
• Using dedicated extraction software like VCDGear.
• Using 3rd party copy utilities (e.g., TeraCopy or FastCopy).
  • Note: Total Commander will trigger it because it utilizes standard Windows copy APIs by default.

🧬 The Root Cause: VCDs vs. ISO9660

Users often assume VCDs are standard data discs. In reality, they are fundamentally different.

While they appear as iso9660 filesystems, they are not. If you attempt to use filesystem entries as anything other than pointers to file starts, you will point to invalid data off the disk.

The "ISO Gateway" Concept: The large $\approx 600 \text{ MB}$ file seen on the first track is not a conventional file; it is an ISO gateway. Because Windows prohibits applications from having raw device access, the iso9660 driver emulates raw track reading through this gateway.

• Linux Behavior: Linux does not allow this type of copying, which often frustrates users but prevents system instability.
• Windows Behavior: Windows attempts to ignore errors during the copy, which leads to the crash.

Furthermore, because VCDs lack standard error detection and correction (EDC/ECC), copying the .dat files multiple times often results in non-identical files.

🏁 Conclusion and Recommendations

Copying VCDs via Explorer was always a suboptimal method, but it was widely used because the UI suggested it was possible. A 2023 update turned this inefficiency into a system-breaking bug.

Recommended Workflow for VCDs:

1. Extraction: Use VCDGear to extract AV content and repair MPEG stream errors.
2. Imaging: Use imaging software to create a bin+cue clone.

The author reported this via the Feedback Hub in late 2025, but Microsoft has provided no confirmation or fix. While rare, any bug impacting core system stability is a concern.