Usb For Mac Not Working
First we need to check your Finder preferences and ensure external disks are set to mount to your desktop.

With the Flash Drive connected to the USB port of your computer:
1. Click Finder in the upper left corner of the screen and select Preferences
2. Ensure the check box next to External disks is checked
Sep 18, 2020 10 Fixes for USB Not Showing Up on Mac. The reasons behind the problem of a USB device not showing up are various, including the USB port is not working, USB drive corruption, virus infection, macOS faulty, etc. So, to figure out the effective solutions for your own case, you need to take time to have some basic check, exclude the irrelevant. USB ports not working in Mac issue is getting contagious. Almost every new update ensues a plethora of complaints from users about their USB ports. While Apple is working hard to give its fixes officially in the coming updates, there is an easy way to fix USB ports not working in Mac problem. However, when running it under Mac OS X 10.4.11 Tiger, the operating system doesn't seem to read the card! I plugged a USB 2.0 thumbdrive with an LED into the card, and the LED flashed and then went on steady, indicating the card was getting power, but nothing showed up on the OS.
If the Finder preferences are set to mount external drives to the desktop we will need to determine if the USB flash drive is detected by the computer
1. Double click the MAC HDD
2. Double click Applications
3. Double Click Utilities
4. Select System Information
5. On the left side selectUSB
Usb For Mac Not Working Windows 10

If you see Flash Drive listed under the USB hub the USB flash drive is detected properly. You can verify is the drive is mounted by Selecting 'Go > Go to folder' from the file menu and typing /Volumes/ (Note: This is case sensitive). This will open the mount point for all drives connected to the Mac computer. You should see the drive mounted here.
Usb For Mac Not Working Mac
If the USB flash drive is not listed under USB hub please verify other USB devices work properly and if possible test the USB flash drive using a different computer.If the USB flash drive is not detected on other computers or if other USB devices are working properly on this Mac then most likely the USB drive is not functional.
Usb For Mac Not Working Mac
If the USB drive appears non-functional per the above troubleshooting, please contact SanDisk support for further assistance with warranty.
