In order to help you, please provide more information:
- Provide exact and full name/version of your board (for e.g. LimeSDR-Mini v1.2), you can find it on board silkscreen.
- Was it working before?
- Do you see any LED activity when you plug your board?
- Are you using any low quality USB hubs, extensions cables? Try connecting directly to USB3.0 port of your PC.
- Download FT60X Chip Configuration Programmer from Utilities - FTDI , read FT601 IC configuration and paste screenshot here.