This fixed it.
Step 1: Put your handset in Airplane mode.
Step 2: Go to Settings on your device and go to Apps.
Step 3: Swipe to All and scroll down and locate Google Services Framework, tap it.
Step 4: Tap on Force Stop, and then tap Clear data and Clear cache.
Step 5: Go back, turn on Wi-Fi (with Airplane mode still on) and connect to your Wi-Fi network. And in Settings, scroll down to About and then tap on System updates. Now tap on Check now.
Step 6: You should see the Android 4.3 update on the screen. Simply install.
Sent from my HTC One using xda app-developers app