Trouble updating via USB-C (Mac)

Macs leave behind duplicate traces of files even when you think you removed all old versions. That includes files in the Trash directory. If you run into this, follow these steps:

1. Connect the USB-C stick to the computer. If you haven’t already, copy the new update file onto the USB-C drive.
   
   Note: When you move a file onto a drive, your Mac will create hidden files. You will remove those hidden files next. By fetching the new update file first, you remove the hidden files also for that file, which is what you want. 
2. Open a Terminal window:
   
   Click the magnifying glass in your Mac toolbar, then start typing terminal
   
   When ‘terminal’ appears and is highlighted, click Return to open
   Open a new terminal window from the drop down menu, or by entering
       COMMAND-N
   
   
3. Change directory to the USB stick:
   
   In the terminal window, type
       cd /Volumes/USB_NAME/
               –> swap “USB_NAME” for the name of your USB stick.
                   You can see the name in your Finder window, or type ls /Volumes/ 
4. Find all old update files on the USB-C stick, including any in the Trash:
   
   In the terminal window, type
       find .                       –> That’s “find” followed by a space and a period
   
   You might be surprised – it can be a long list.
   
   
5. Delete every older update file on the USB, including any in the Trash. Look for anything ending with .shs – you need to remove all of them even if the name before .shs is different from the new file. Leave only the new one. It will start a single period and a forward-slash, then the name: ./update.shs. Most importantly, remove the file starting with period-slash period-underscore:
       rm ./._update.shs
   
   
6. After you have deleted all old files, type find . again and scan the list. You should have only one file left. You’ll need this one for your update:
       ./update.shs
   
   
7. When you’re done, type
       cd
   
   This returns the terminal focus to your Mac hard drive and lets you eject the USB stick from the Finder as usual by clicking the small eject arrow next to the USB-C drive name. 
   
   
8. Now you’re ready to update each Milo by inserting the USB-C drive into each Milo.
   
   
9. If you want to learn more about removing files like these from your Mac, search online for “How to delete ._ duplicate files from USB drive” or How to delete dot underscore files from USB drive“