If your computer is not detecting your external hard drive after a software update, here are some steps you can take to try to fix it:

1. Verify that the external hard drive is plugged in and turned on.
2. Confirm that the file type of the drive is supported by your computer.
3. Check that the cable used to connect the drive to your computers is working by testing it with another device.
4. Attempt to access the data on your external hard drive by connecting it to a different computer.
5. If the external drive is still not detected, consider backing up your data and formatting the drive for use with your computer.