I have a problem with my app when I use "Build and Go" with my iPhone. When the application is already installed on the phone I get the following message: Your mobile device has encountered an unexpected error (0xE8000036) during the install phase: PreflightingApplication In the organizer this is what appears in the console: Sun Oct 12 22:57:05 unknown mobile_installation_proxy <Error>: preflight_application_install: The application has already been installed Sun Oct 12 22:57:05 unknown mobile_installation_proxy <Error>: install_application: Could not preflight application install Sun Oct 12 22:57:05 unknown mobile_installation_proxy <Error>: handle_install: Installation failed When I uninstall the app first I can use "Build and Go". Is this normal? I recently added a settings bundle and now I have to 1. Uninstall the app from the iPhone 2. Re-enter the settings in the settings app 3. Press Build and Go 4. Debug I just want XCode to update the application after I add a few lines of code. What am I doing wrong? I searched a lot in google but it seems like I'm the only one having this problem. It does work when I try the same in the iPhone Simulator. Thanks for your help.