I changed the project and the target build Architectures settings to what I think are the default values. There are no excluded architectures, and there is no VALID_ARCHS setting as far as I can tell. I am attaching screenshots of my settings. I am still getting the same error when I try to run the simulator. Please help.

Thank you for your reply! I am using x86_64$(ARCHS_STANDARD) Architectures in both project and build settings. I also tried using arm64, armv7$(ARCHS_STANDARD), which worked in previous versions of XCode, but on XCode 13 it no longer works. I get the same error message as shown in my previous post. Here are the project build settings: And here are the target build settings. Deployment target is iOS11 for both

Thank you so much for your reply! I really appreciate hearing from someone. In answer to your questions, I am using XCode 13 on Mac OS 11.6. It says appname (appname|project), where "appname" is in place of the name of our app, which I blackened out. Actually I solved the problem by going into the Product menu, then selecting "Scheme", then "Manage Schemes". Somehow the scheme for my project got added twice. When I deleted one of them the problem was solved.

I did what you suggested, but when I try to run the app on the iOS 15 simulator I get the following message: "App's architectures (Arm64) include none that iPhone 11 can execute (Intel 64 bit)." Any ideas as to what I could do ?