After trying a few different things, Dell-Cares recommended I do a clean reboot. That fixed it. How to perform a Clean Boot in Windows 10 to troubleshoot software conflicts I guess I will now have to find the guilty program. The only step after that would have been to reinstall Windows, which I don't think would be worth it, considering DMC is a low priority program.
When I bought my computer DMC (Dell Mobile Connect) worked well. After a few weeks it quit working. I have rebooted both my PC and iPhone. I have uninstalled and reinstalled the app and driver countless time. Each time, the result is the same. When the PC app starts to launch, nothing happens, then after about 15 seconds it crashes. It doesn't even give my time to change any settings. My iPhone and PC still show a Bluetooth connection. In Event Viewer, the Event ID is 1000.
Inspiron 15 5584, iPhone, DMC crashes