Mac OS cannot detect my new CardBus or ExpressCard expansion card. What do I do?

To determine if Mac OS detects your expansion card, you need to check System Information to see if the card is listed under the appropriate heading or is listed with an error (for example, Device has not been configured). An example of an appropriate heading for a network card is Ethernet Cards. The expansion card is listed in System Information as the name of the chipset. You can find the name of the chipset on the Technical Specifications tab for the product ID on https://www.startech.com/Support.

To open System Information, complete the following:

1. In the upper-left screen, click the Apple icon.
2. Click About This Mac.
3. Click More Info or System Report.

If you install a new CardBus or ExpressCard expansion card and Mac OS cannot detect the card, you can complete the following troubleshooting tasks to help to resolve the issue:

• Turn off the computer, unplug the power cord, and remove the expansion card. Put the card back into the computer, making sure to apply firm pressure across the entire card. Press the expansion card as far into the slot as it can go. The expansion card should click into place. 
• Put a different expansion card in the slot that is experiencing the issue with the new expansion card.
• Put the new expansion card in another computer.

If you completed the previous steps and determined that the problem is not with the card or expansion slots on the motherboard, you may need to update the EFI firmware on your system.