Is your USB setting set for charging only? You may need to change it to MTP (Media Transfer Protocol). Not sure where it is on your Droid Z Force, but on my Droid Turbo 2 it is in Settings->Developer Options->Select USB Configuration. You might look at: How to Enable USB Debugging Mode on Motorola Moto Z / Z Force / Z Play
The User Manual https://ss7.vzw.com/is/content/VerizonWireless/Devices/Motorola/Userguides/moto-z-force-ug.pdf has a section (page 54) on the USB-C cable use and settings for file transfer as opposed to charging only.
From the User Manual:
To load music, pictures, videos, documents, or other files to
and from your computer, connect your phone to your
computer with a USB-C cable.
To transfer files, you need to specify the type of USB
computer connection you want to use. Swipe the status bar
down and tap USB for charging, then select the
• File transfers (MTP)
Being able to connect your phone to your PC is crucial to being able to manage and store your items effectively. We will gladly assist you so that your PC recognizes your phone. In the posts submitted by jav6, there is some really helpful information as you may need to enable debugging mode in order to proceed. Once that is done here is a link that will assist you with selecting the USB mode and transferring items to your PC. https://www.verizonwireless.com/support/knowledge-base-205235/. Are you getting caught up on any of the steps provided? What exactly are you trying to accomplish when you plug your phone into your PC via USB?
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