iPhone USB Connection Issue on Mac: How to Fix Repeated Connect and Disconnect Problem

When connecting an iPhone to a Mac, the connection kept getting established and disconnected repeatedly. Despite replacing the cable with a new one, the same issue persisted. Considering that both the iPhone 6 and the 2015-model Mac were relatively outdated, it was difficult to determine which device had the problem. Upon searching the internet for related information, many users were found to be experiencing similar issues. Various solutions like resetting the SMC were attempted, but ultimately none of them resolved the issue. However, after finding a commonly agreed-upon solution, it turned out to be simpler than expected. After temporarily disconnecting the USB, running the following command in the terminal resolved the issue:

sudo killall -STOP usbd

This command likely temporarily stops the USB service. However, since it seems that the system automatically restarts the service, it was possible to achieve a reboot-like effect. By using this method, the connection problem between the iPhone and Mac was resolved, allowing for smooth usage.