AT&T HTC One com.android.phone has stopped

[Nick Willems]

So here's the story: my phone was working fine this morning and I restarted as I do periodically. When it started back up it displayed the error: "unfortunately com.android.phone has stopped working", if I tap OK, there is a half second delay, then the message reappears. I tried restarting the phone which didn't work, then I went and did a factory reset which also didn't work: the same error message continuously appears. It has been a while since I did any software update (since 4.3 was released) and I can think of any significant changes that I've made recently that could have triggered this. I'll be visiting the AT&T store tomorrow but I wanted to see if anyone could spare me that pain...