Sign Check Error: Daemon Tools

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 The long answer involves driver signatures, Secure Boot, and outdated certificates.

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

Method 4: Reinstall Daemon Tools (The Clean Way)

A standard reinstall often fails because the problematic driver remains in memory. You need a clean reinstall.

Step 4.1: Uninstall using the official tool.

  • Download the "Daemon Tools Clean Tool" from the official Disc Soft website (do not use third-party uninstallers).

Step 4.2: Manually delete leftover drivers.

  • Open C:\Windows\System32\drivers\
  • Look for files named dtsoftbus01.sys, dtlitescsibus.sys, or dtprobus.sys. Delete them if present.
  • Note: You may need to take ownership or boot into Safe Mode to delete these.

Step 4.3: Remove registry leftovers.

  • Press Win + R, type regedit, navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\
  • Delete any keys named dtsoftbus01, dtlite, or dtpro.

Step 4.4: Reboot and reinstall.

  • Download the latest version from the official Daemon Tools website. Avoid "cracked" or old versions—they are guaranteed to trigger sign check errors.

Daemon Tools: Sign Check Error — Informative Feature

3. Enable Test Signing Mode (Permanent but less secure)

Run Command Prompt as Admin and execute:

bcdedit /set testsigning on

Reboot. You’ll see Test Mode watermark on desktop.
Now install DT. To disable later:

bcdedit /set testsigning off

Solution 3: Install SPTD Driver Manually

Sometimes the Daemon Tools installer fails to install the underlying SPTD driver correctly. Installing it separately can bypass the error. Resolved: How to Fix the "Daemon Tools Sign

  1. Download the standalone SPTD Installer (search for "SPTD driver download" on the official DuplexSecure or Disk-Soft website).
  2. Run the SPTD installer.
    • If you get the sign error here, perform Solution 2 first, then run this installer.
  3. Once SPTD installs successfully, restart your computer.
  4. Now run the Daemon Tools installer.

Step-by-Step Solutions

What is the Sign Check Error?

The "Sign Check Error" typically appears during installation or startup of Daemon Tools (especially versions before DT Lite 10). It means the software’s kernel drivers (dtsoftbus01.sys, dtlitescsibus.sys, etc.) lack a valid digital signature or Windows has blocked them for security reasons.

Common error messages:

  • "Sign check error. Please reinstall program."
  • "Driver signing check failed"
  • "Digital signature cannot be verified"

Part 3: 9 Ways to Fix the Daemon Tools Sign Check Error

Why Does This Happen?

| Cause | Explanation | |-------|-------------| | Windows Driver Signature Enforcement (most common) | Modern Windows (8, 8.1, 10, 11) requires all kernel drivers to be signed by Microsoft. Old DT versions use outdated signatures. | | Corrupted installation | Missing or damaged driver files. | | Antivirus interference | Some AVs quarantine or strip signatures from DT drivers. | | Expired certificate | Daemon Tools’ old SHA-1 certificate may be expired or revoked. | | Test mode disabled | DT sometimes requires Test Signing Mode to load unsigned drivers. |