Daemon Tools Sign Check Error [work] Today

Resolved: How to Fix the "Daemon Tools Sign Check Error" (Full Guide)

Experiencing the "Sign Check Error" in Daemon Tools? You are not alone.

For over two decades, Daemon Tools has been the industry standard for mounting disc images (ISO, MDX, MDS). However, long-time users and new adopters alike occasionally run into a frustrating roadblock: the dreaded "Sign Check Error" (often accompanied by codes like 0x20000 or a driver signature failure).

This error typically appears during installation, updating, or when trying to run the virtual SCSI driver. The result? Daemon Tools refuses to install, the virtual drive vanishes from "My Computer," or the software crashes immediately upon launch.

Why does this happen? The short answer is Windows security. The long answer involves driver signatures, Secure Boot, and outdated certificates. daemon tools sign check error

In this article, we will explain exactly what the Daemon Tools sign check error means and provide nine proven methods to fix it permanently.

Advanced Fix (Editing Registry & Group Policy)

To permanently allow unsigned drivers (Windows Pro/Enterprise):

  1. gpedit.msc → Computer Config → Admin Templates → System → Driver Installation
  2. Enable "Allow administrative override for device driver installation policy".
  3. Then in same path → "Code Signing for Device Drivers" → set to Ignore.

Registry method (all editions):

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Driver Signing]
"Policy"=hex:01

Reboot after change.

Method 2: Enable Test Mode (Permanent for Non-Signed Drivers)

Test Mode allows you to run unsigned drivers without rebooting. A watermark will appear on your desktop ("Test Mode"), but this is harmless.

Steps:

  1. Open Command Prompt as Administrator (Right-click Start > Terminal (Admin)).
  2. Type the following command and press Enter: 
    bcdedit /set testsigning on
  3. Close the window and restart your PC.
  4. Install Daemon Tools. The sign check error should disappear.
  5. To turn Test Mode off later: bcdedit /set testsigning off

Method 5: Disable Driver Signature Enforcement (Temporary Boot Option)

If you get the error immediately after a Windows update, Microsoft may have blacklisted the specific driver version. You can bypass this for one session.

Note: This is a temporary fix. If it works, you need to update Daemon Tools to a version with a Microsoft-approved signature.

Understanding the Error

The error occurs because of Windows Driver Signature Enforcement. Daemon Tools relies on a kernel-mode driver (SCSI Pass Through Direct, or SPTD) to create virtual drives. For security, Windows requires all kernel drivers to have a valid digital signature. If the Daemon Tools installer or driver is old, or the signature has expired/revoked, Windows blocks it, resulting in this error. Resolved: How to Fix the "Daemon Tools Sign

Step 5: Prevention for the Future