Cause: The PC/SC service is not running, or the app is looking for a different reader name.
Fix:
Cherry originally provided the EZ100PU_WindowsDriver.zip package. While Cherry no longer actively supports this reader, the final Windows 10 driver (version 3.0.3.0 or 4.2.0.0) works perfectly on Windows 11.
pnputil -i -a C:\path\to\ez100pu.inf
Select device in Device Manager → Update driver → “Have Disk” → point to .inf.
Warning: Do not use random “driver updater” software from pop-up ads. Most of these are malware. Always source your drivers from official or trusted repositories.
This is the million-dollar question. Given Microsoft’s tightening security model, it is very likely that unsigned kernel drivers for Ez100pu will be completely banned in the next major Windows release (Windows 12, expected around late 2025/early 2026). Ez100pu Driver Windows 11
Your best strategy today:
While this article focuses on making the Ez100pu work, you must consider hardware obsolescence. The Ez100pu uses the T=0 and T=1 protocols at a maximum speed of 9600 baud. Modern cryptochips on new ID cards (released after 2023) require higher baud rates (up to 400 kbps) and support for ISO 7816 Class A, B, and C.
If you frequently encounter "Card communication error" even after a perfect driver install, it is time to upgrade to a modern reader like the REINERSCT cyberJack RFID or Identiv SCR3500. These have native Windows 11 drivers from day one.
Final Verdict: The Ez100pu is not dead on Windows 11. With the right driver (Microsoft CCID or Cherry v3.0.3.0) and a few tweaks to signature enforcement and power settings, this venerable smart card reader can serve you for years to come.
Forcing Windows to accept legacy driver via registry: Cause: The PC/SC service is not running, or
HKLM\SYSTEM\CurrentControlSet\Control\CI\Policy
Add DWORD: VerifiedAndReputablePolicyState = 0
Effect: Disables Windows Defender Application Control (WDAC) → severe security risk.
Installing the Castles Technology EZ100PU Smart Card Reader on Windows 11 typically requires a manual approach, as the official drivers were originally designed for Windows 7 and 8. Installation Guide for Windows 11 1. Automated Driver Update
Windows 11 may have a compatible generic driver in its database. Plug in the reader and open Device Manager.
Find the reader (likely under "Smart Card Readers" or "Other Devices").
Right-click it and select Update driver > Search automatically for drivers. Select device in Device Manager → Update driver
If that fails, go to Settings > Windows Update > Advanced options > Optional updates and look for a Castles or Gemalto driver. 2. Manual Driver Installation
If Windows does not find the driver automatically, you can use legacy drivers from reputable sources:
Official Catalog: Search the Microsoft Update Catalog for "EZUSB" or "Castles" to find older signed drivers that often still work on Windows 11.
Third-Party Drivers: Sites like DriverScape and Zagrebačka banka Support provide direct links for the 64-bit EZ100PU driver. Critical Windows 11 Troubleshooting
Many users find that even with the driver installed, the device does not work due to Windows 11 security features.