Problem

• Nothing is displayed in the Variable View in the Xcode debug area, and the "po" command of LLDB does not print anything.

• Nothing is output from the simulator and the following error occurs from the real device.

Environment

• macOS 10.15.7
• Xcode 12.3

Reason

• ???

Attempts

• remove DerrivedData directory
• clean build folder
• restart Xcode app
• reboot the mac
• Change the console output setting to something other than "Target Output" (As you can see in the images, it was always "All Output".)
• Scheme setting check
  • Run → Info → Launch → check on the (it checked on from the begining)
  • Run → Arguments → Invironment Variables → remove OS_ACTIVITY_MODE (It wasn't exist from the beginning)
• Project → Build Settings → Swift Compiler — Custom Flags → Other Swift Flags → -D DEBUG (I try this way but it still doesn't work.)
• Try this with a different project → works fine