Xcode: "This app could not be installed at this time."
I know the question has been answered but for others encountering the same issue I suggest following:
Check simulator logs, if its printing something useful. First, selecte simulator then from menu option open Debug -> Open System Logs.
Make sure only 1 simulator is running.
Delete the older version of app from the simulator.
If you importing a custom framework, make sure custom framework->bundle-id is not same as currentAppProject->bundle-id. If you are not sure then simply change the bundle-id of current project.
Also some of the simulators can be buggy -> Simply change the simulator, it may resolve the issue, for me changing the simulator worked.