Xcode attempted to locate or generate matching signing assets and failed to do so

I'm also facing this issue as a 'Team Member' role. The 'You are not allowed to perform this operation' warning leads me to believe that XCode is more strictly enforcing the roles defined here: https://developer.apple.com/programs/roles/

Even though I have access to the signing assets (certificate and provisioning profile), XCode won't allow me to specify them. Try upgrading your role to Team Admin.

Updated 2014-09-29:After extensive research, I've found it is possible to generate the .ipa using xcodebuild from the command line even as a 'Team Member' role using the following:

xcodebuild -exportArchive -archivePath $projectname.xcarchive -exportPath $projectname -exportFormat ipa -exportProvisioningProfile "Provisioning Profile Name"

credit to 1

Note: As pointed out in the linked article, the "Provisioning Profile Name" is the name specified in the name field of the certificate (viewable from developer.apple.com).

You can automate the process in xcode by including the call into your project build script.

Try to open your console and go to your Xcode project folder then type these commands:

to clean your project

xcodebuild clean -project YourProjectName.xcodeproj -configuration Release -alltargets

to build and archive your app

xcodebuild archive -project YourProjectName.xcodeproj -scheme YourSchemaName -archivePath YourProjectName.xcarchive

You can simply find YourSchemaName in Xcode > Product > Scheme > Edit Scheme...

finally to create your app .ipa file

xcodebuild -exportArchive -archivePath YourProjectName.xcarchive -exportPath YourProjectName -exportFormat ipa -exportProvisioningProfile 'Your Provisioning Profile Name'

To find Your Provisioning Profile Name please login to Apple Developer Member Center and go to Certificates, Identifiers & Profiles, then click on Provisioning Profiles for iOS Apps. There you will find Your Provisioning Profile Name.

If it does not work try to replace single quote with double one ( ' with " ).

You will find .ipa file in your Xcode project folder.

After this you will able to open your .ipa file in iTunes and install on your iOS device.

I hope it helps!

What's happening: Xcode need to sign build with valid Certificate. It is trying to locate one with no luck. Why? Because before Xcode6, you were allowed to sign AdHoc builds with your's developer certificate. And you were able to, because you have a private key for it. But now you need to sign Ad Hoc builds with Production Certificate. And you don't have a private key for it.

So steps required to make it possible to build from Xcode6 (https://stackoverflow.com/a/26061067/1918302):

1. Get a private key for your Production Certificate. (You need to export it from Mac keychain it has and import to your's keychain OR Revoke current and Create New production certificate. During creation you'll get one. Quoting here from link above:

   BEWARE: revoking an enterprise distribution certificate invalidates all apps that were signed and deployed with that certificate (official info)).

2. Create special XC Ad Hoc: Distribution provisioning profile (if you have Admin role in your team on developer.apple.com - Xcode will do this for you).

3. Set provisioning profile in your project's target -> Build Settings -> Code Signing to this created in step 2.

Done!

OR if those above not achievable, you can make a build using command line tools: https://stackoverflow.com/a/25979784/1918302. But this seems to me as security hole and I don't believe that this will work for long time.