I have upgraded my Xcode from 10.3 to 12.4, but got the two annoying issues when I built and run previous app project with new upgraded Xcode.
Issue #1
Got following build error when I built the old project with Xcode 12.4 (it is good with Xcode 10.3).
ld: in /Users/project_path/Pods/GoogleAnalytics/Libraries/libGoogleAnalytics.a(GAIUtil.o), building for iOS Simulator, but linking in object file built for iOS, file '/Users/project_path/Pods/GoogleAnalytics/Libraries/libGoogleAnalytics.a' for architecture arm64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
Issue #1 Solution
Go to Build Settings
-> Excluded Architecture
and set arm64
in the excluded architecture as following screenshot.
Then I can build the project successfully.

Issue #2
I got another error when trying to run the app in simulator as following:
The file “app_name” couldn’t be opened because you don’t have permission to view it.

Issue #2 Solution
- Choose PROJECT and then go to
Build Settings
->User-Defined
, and delete wholeVALID_ARCHS
. - Choose TARGETS and then go to
Build Settings
-> delete wholeVALID_ARCHS
.

Issue #3
Even though I can run the app in simulator, but got following error when trying to run in iPhone XR device.

This does because we added arm64
into the Excluded Architecture
, so need to delete the added item when trying to run in a real device instead of simulator.
Summary
Finally, I can run the app with Xcode 12.4 and simulator and my iPhone device.