Attiny dev board - usb device not recognised

I have just purchased two dev boards like this
I have a number of attiny 45's
most of them just light the left led on the board when plugged in , one lights both leds (a solid light, no flashing) but both boards show a box just above the task bar that says
usb device not recognised
every time I plug one in.

Is there any way to tell if this is two duff boards or duff chips?

I have all the software in the ide for attiny microcontrollers and did manage to program one chip using a board I made up that straddled the uno pins a while ago (the chip that lights both leds) but I don't know where the board is now?

Have you loaded code onto the chip to make it respond to USB (ie, some VUSB implementation)? If not, it should come as no surprise that the chip is unable to communicate over USB.

I wager the intent of those is to fir them with '85's loaded with digispark or trinket bootloader on them, so that they can be programmed over USB. That approach is less well suited for the '45 because of how large the VUSB bootloaders are.

The '85 doesn't have real USB support at all (just what you can do using VUSB to emulate USB) - I find it disappointing to see how many people are being led astray by the profusion of documentation-free digispark/trinket clones and thinking that means that it's just plug and play this thing has full USB and all.