"Warning: unable to build chain to self-signed root for signer" warning in Xcode 9.2

Question

I'm attempting to migrate an Xcode project to another computer. It gives me the warning "Warning: unable to build chain to self-signed root for signer" and when it runs it crashes immediately similarly to what is shown in this Stack Overflow:

App working on simulator but not on iPhone( dyld`__abort_with_payload dyld`_dyld_start)

My issue seems similar to what is described on the Apple Developer Forums here: https://forums.developer.apple.com/thread/86161

and similar to what is described on this Stack Overflow: Xcode ios app development code signing

except the suggestions of deleting certificates and re-adding them, re-adding my account and restarting didn't seem to help. I have removed my developer cert for the second time and now I don't see it coming back, and I'm at a loss of knowing how to get it back since my dev portal doesn't appear to have a place to download it like it used to.

I've also tried deleting the derived data folder several times.

e: I've determined ANY project on this computer results in the same crash and warning.

Answer 1

If none of the other solutions work, try adding the intermediate signing certificates to your system keychain. I found this while trying to manually create provisioning profile/certificates as nothing else was working - from the Create a New Certificate step of the New Provisioning Profile process on Apple Developer platform:

To use your certificates, you must have the intermediate signing certificate in your system keychain. This is automatically installed by Xcode. However, if you need to reinstall the intermediate signing certificate click the link below: Worldwide Developer Relations Certificate Authority (Expiring 02/07/2023) Worldwide Developer Relations Certificate Authority (Expiring 02/20/2030)

After downloading these two files and double-clicking them to automatically add to the system keychain, the automatic provisioning profile in xcode started working (I didn't need to complete the manual provisioning profile process, but that's where I found the links)