On occasion, Xamarin can throw up some weird and frustrating errors, and recently I have been experiencing: “Error error HE0046: Failed to install the app”. After some frantic googling it seems that this isn’t a new error and has sporadically stymied developers without rhyme or reason for a few years. The reason for it seems unclear however I have found a workaround that seems to work, for now. In the “Solution Explorer”, right-click the ios project, then select build and then point the “Output Path” to somewhere outside of the application folder. You should find that the application will now deploy and run on the simulator again.
Hope this helps and please let us know if you have any more information on the issue.