Can't run Tests for iOS locally

I got Appium to run on Saucelabs the other day and since then have not been able to make it run locally. My Caps are:

desired_caps = {
caps: {
appiumVersion: ‘1.6.3’,
platformName: ‘iOS’,
platformVersion: ‘10.2’,
deviceName: ‘iPhone 7 Plus’,
app: ‘/Users/me/Library/Developer/Xcode/DerivedData/APPNAME-gubabnwufgbwhqesmkcmrlltnbca/Build/Products/Debug-iphonesimulator/’,
Appium.promote_appium_methods Object

The above fails because Sauce can’t find the app which is fine - I just don’t understand why the app is not being launched locally. Below is what my Appium server contains shows when started.

[Appium] Welcome to Appium v1.6.3
[Appium] Appium REST http interface listener started on

I can also run the inspector off the server using the Appium App - so I know the build works - but can’t seem to get my tests to run locally. Am I missing something? This all seemed to start when I upgraded to 1.6.3 and using platformVersion 10.2.

When I look at the failed Sauce job it says:
Base config
“app”: “/Users/me/Library/Developer/Xcode/DerivedData/APPNAME-gubabnwufgbwhqesmkcmrlltnbca/Buil…”,
“platform”: “ANY”,
“browserName”: “”,
“version”: “”,
“deviceName”: “iPhone 7 Plus”,
“platformName”: “iOS”,
“appiumVersion”: “1.6.3”,
“platformVersion”: “10.2”

Then reason for failure is not surprisingly:
Failed to download mobile app: /Users/me/Library/Developer/Xcode/DerivedData/APPNAME-gubabnwufgbwhqesmkcmrlltnbca/Build/Products/Debug-iphonesimulator/; unsupported protocol ‘’ in URL

If I run it with the sauce-storage app location it runs just fine on sauce.

Anyone have any thoughts on what is going on here - I am completely stuck on this issue. Is there any other trigger other than app location that tells it to run locally VS on sauce? Any insight or tips would be hugely appreciated.