Apps similar to USBGuard include AccessPatrol. It's paid, but USB Protector is free. Other options are Gilisoft USB Lock, MyUSBOnly, USB Block and DeviceLock. In total there are seven apps like USBGuard for Windows, Mac and self-hosting.
Monitor and block USB device use in your organization to protect sensitive corporate data against theft. Includes device control features for WiFi, Bluetooth, Printers & more. Block/allow on a per-user per-computer, or per-department basis.
Canada
GiliSoft USB Lock is a data leak prevention tool that prevents leakage and copy of your data to USB Drives (Android phone/iPhone), External Drives, CDs/DVDs or other such portable devices.
China
Endpoint security solution MyUSBOnly prevents unauthorized access to USB devices and Prevent sensitive data from leaking out and secure your files
This application is able to target and block specific USB, network, and bluetooth storage devices from connecting to your computer. Depending on your settings, you can be prompted every time a new device is detected, or either allow all of a type of storage automatically, or...
Block or specifically allow devices from being used such as CD and DVD drives, USB drives, firewire, infrared, and more.
Download USB Protector - Remove Autorun viruses from USB removable storage devices and pendrives
NetWrix USB Blocker enforces centralized access control to prevent unauthorized use of removable media that connects to computer USB ports, for example, memory sticks, removable hard disks, iPods, and more.
United States
