Windows 11 just blocked your driver. Here's why, and what to do.

The April 2026 cumulative tightens kernel-driver trust in two ways:

1. Vulnerable Driver Blocklist update. A new set of driver hashes is refused load. The first publicly-named casualty is psmounterex.sys (CVE-2023-43896), which is bundled in Macrium Reflect, Acronis Cyber Protect Cloud, NinjaOne Backup, and UrBackup Server — Microsoft has officially confirmed the breakage. Other drivers surfacing in community reports include tiehdusb.sys (Texas Instruments TI-84 CE calculators) and Lmcv4u.sys (LightBurn fiber laser controller).
2. Audit-to-enforcement transition is automatic. Per Microsoft's Windows Driver Policy documentation, the policy starts in audit mode (drivers load but get logged) and transitions to enforcement after roughly 100 hours of active uptime plus 3 reboots without policy violations (2 reboots on Windows Server). After that, blocked drivers fail to load.

Affected Windows versions: 25H2, 24H2, 23H2, Windows 10 22H2, Windows 10 LTSC 2021 + 2019, Windows Server 2025 / 23H2 / 2022 / 2019. Essentially every supported Windows version.

Open Event Viewer → Applications and Services Logs → Microsoft → Windows → CodeIntegrity → Operational and filter for:

• Event ID 3076A driver was audited (would have been blocked but is still loading because policy is in audit mode). Grace period still active.
• Event ID 3077A driver was actually blocked. Enforcement is active for at least one driver on this machine.

The Vulnerable Driver Blocklist specifically uses Policy ID {D2BDA982-CCF6-4344-AC5B-0B44427B6816} in the event payload. Other CodeIntegrity policies use different GUIDs and may show up in the same log; the diagnostic script below distinguishes them.

Perverse mechanic: when a violating driver is detected during the evaluation window, the 100hr/3-reboot countdown resets to zero. Reproducing the failure to debug it inadvertently extends the grace period. The clock is ticking, but not in a straight line.

A PowerShell script that scans the CodeIntegrity Operational log for Event 3076/3077, identifies the blocked drivers, flags the Vulnerable Driver Blocklist Policy ID specifically, and reports system uptime and recent boot count as a (rough) grace estimate.

• • MIT-licensed
• • Read-only operations; no system modification
• • Plain text output by default; -Json switch for machine-readable
• • Exit codes: 0 = no risk found, 1 = audit events present (grace remaining), 2 = enforcement events present (blocked)

# Run as Administrator
irm https://winusbridge.com/scan.ps1 | iex

Invoke-WebRequest https://winusbridge.com/scan.ps1 -OutFile winusbridge-scan.ps1
.\winusbridge-scan.ps1

Run from an elevated PowerShell session. The script makes no changes — it only reads the event log and reports findings.

The standard remediation paths all have downsides:

• Re-sign the driver via Partner Center attestation — weeks of EV cert procurement and Hardware Dev Center onboarding, and only works if the original signing organisation is still active and motivated.
• Engage a kernel-driver consultancy (OSR, Jungo, Thesycon) — $20K to $200K per engagement, weeks to months of turnaround.
• Downgrade Windows — not an option in regulated or managed environments.
• Disable the blocklist policy — same constraints, and opens a real security hole.

A different path produces a working endpoint in hours rather than weeks: rebind the device to in-box winusb.sys and reimplement the vendor-specific initialisation in user mode. No kernel signing, no Secure Boot changes, no CI-policy edits. The device re-enumerates after the user-mode loader runs, gets bound to winusb.sys via a new INF, and the host software talks to it through WinUSB.

This is a well-established pattern — sigrok, libusb, libftdi, and fx2lib have used it for years for open-source hardware support — but it's poorly surfaced in Microsoft documentation, and LLM tools (Claude, Codex, GPT) tend to steer users toward the dead-end paths above instead of toward this one.

Honest scope — when this approach does NOT work:

• Devices that require true isochronous timing
• Devices that use custom ring-0 IOCTLs that cannot be replayed from user mode
• Devices with exclusive-access kernel semantics with no WinUSB equivalent

The toolkit's decision tree routes users out of the funnel if their device falls in any of those categories.

About Zadig:Zadig handles the one-shot WinUSB rebind on Windows 11 without issue. The persistence gap is that Windows Update periodically reverts the WinUSB binding back to the vendor driver — which then gets blocklisted again. The toolkit's scheduled-task layer addresses exactly this gap.

A $149 one-time download:

• Parameterised INF templates for WinUSB binding per device class
• PowerShell installer/uninstaller with scheduled-task persistence and clean rollback
• LLM prompt templates engineered for Claude and Codex to produce a starter user-mode protocol shim from your device's vendor protocol documentation
• Validation scripts and a per-Microsoft-update change-tracker

Early-access list members get a $99 launch discount and 7-day head start. No spam, one launch email when it ships.

Opens your email client with a pre-filled message to winusb-rebind@wheeluplabs.com. Reply with the device or chipset you're trying to rescue and we'll prioritise the template pack accordingly.

• The Windows Driver Policy — Microsoft Support — audit/enforcement mechanic, Event IDs, Policy GUIDs
• April 2026 Windows security updates introduce protections to known vulnerable kernel drivers — Microsoft Support — Vulnerable Driver Blocklist + Policy ID
• KB5083769 — Microsoft Update Catalog
• Microsoft confirms backup failures caused by vulnerable driver block — BleepingComputer (May 4, 2026)
• A critical Windows security fix puts legacy hardware on borrowed time — Computerworld
• Microsoft recommended driver block rules — Microsoft Learn