: This Windows security feature frequently blocks multikey.sys (often resulting in Code 39 errors) because the driver does not meet the strict memory protection standards of modern Windows.
Open Command Prompt as Administrator in Safe Mode and run:
Expand the category, right-click the MultiKey device, and select .
It creates a "Virtual USB MultiKey" entry under System Devices in the Device Manager. 2. Security and Risks multikey.sys windows 11
Right-click the device and choose . Ensure you check the box that says Attempt to remove the driver for this device . Step 5: Run System File Checker (SFC)
Based on this report, we recommend:
If you're encountering problems related to multikey.sys, try the following troubleshooting steps: : This Windows security feature frequently blocks multikey
This feature in Windows Security can prevent "vulnerable" drivers from loading even if they are signed.
| Attribute | Value | |-----------|-------| | | multikey.sys | | Typical Location | C:\Windows\System32\drivers\ | | Developer | Oleg Kozlov / ATNSOFT | | Associated Software | MultiKeyboard, Key Remapper | | File Type | Kernel-mode device driver (.sys) | | Digital Signature | Often signed, but may use SHA-1 (problematic on newer Windows 11 builds) | | Typical Size | ~15–50 KB | | Service Name | MultiKeyboard or similar | | Start Type | Boot or System start (typically 0 or 1 in registry) |
The file is a third-party Windows driver often encountered by software developers, gamers, and IT professionals. If you recently upgraded to Windows 11 or ran a malware scan, you might have flagged this file. Step 5: Run System File Checker (SFC) Based
However, situations arise where a physical dongle may be lost, damaged, or unavailable. In such cases, multikey.sys acts as a virtual dongle, tricking the software into thinking a physical hardware key is present. This is why it is frequently associated with software such as SolidCAM, MasterCAM, EPLAN, and others.
While multikey.sys was once widely tolerated for running legacy emulated software, it is inherently incompatible with the hardened security design of Windows 11. Keeping it on your system leaves you exposed to malware exploitation and unstable OS performance. Removing the driver and relying on legitimate software licenses is the best path forward to ensure a fast, secure Windows 11 experience.