Microsoft Defender’s "Tamper Protection" feature prevents any external software from modifying core security drivers. When Kaspersky tries to install klim6sysx64 , Defender blocks the write operation, triggering Error 27300.
If you encounter Error 27300 during the installation of the Klim6sysx64 exclusive driver, follow these troubleshooting steps:
If you have another firewall or a VPN (like NordVPN, AnyConnect, or OpenVPN) active, their drivers might be competing for "exclusive" access to the network stack.
Performing a clean boot can help you identify if any third-party software is causing a conflict. error 27300 error installing driver klim6sysx64 exclusive
klim6sysx64.sys is identified as a kernel driver component (part of their endpoint security suite). The error commonly occurs during installation, update, or uninstallation of Kaspersky products, or when a conflicting security driver (another antivirus) is already active.
Corrupted registry entries governing network interfaces or protocols.
: Ensure the Network Setup Service is present and set to Manual startup. If this service is damaged, it can block the installation of NDIS filter drivers. Common Conflicts to Check Performing a clean boot can help you identify
Technician Elias Thorne stared at the monitor, the blue glow reflecting in his tired eyes. The installation bar had been stuck at 99% for ten minutes. Then, it happened. The dreaded popup:
If the driver is "stuck," you can manually delete the service via the Command Prompt: Open Command Prompt as an Administrator. Type sc delete klim6 and press Enter . Attempt to reinstall the software.
The klim6sysx64 driver was trying to take exclusive control of the port, but the hardware was screaming, 'I'm busy saving us from overheating!' If you have used network-heavy applications
If "Kaspersky Anti-Virus NDIS Filter" appears in the list, select it and click . Solution 4: Reset the Network Stack
Select your specific software version from the drop-down menu (e.g., Kaspersky Endpoint Security, Kaspersky Standard).
If Windows Cryptographic Services fail to initialize or verify the .cat signature files for the new driver, the OS rejects the installation as a security risk.
If you have used network-heavy applications, their virtual adapters might be blocking new NDIS entries.
: Corruption in Windows core networking features prevents third-party NDIS filter injection.