It seems like we're working through the same book/resource haha. I'm also seeing this error, but I've found that going up the call stack to get out of libsystem_kernel.dylib brings me back to the right context. So: (lldb) expr self (Signals.MainContainerViewController) $R0 = 0x0000000109f083a0 { UIKit.UIViewController = { ... } } (lldb) c Process 8065 resuming (lldb) bt * thread #1, queue = 'com.apple.main-thread', stop reason = signal SIGSTOP * frame #0: 0x0000000100e04c10 libsystem_kernel.dylib`mach_msg2_trap + 8 frame #1: 0x0000000100e15da4 libsystem_kernel.dylib`mach_msg2_internal + 76 frame #2: 0x0000000100e0ce34 libsystem_kernel.dylib`mach_msg_overwrite + 532 frame #3: 0x0000000100e04f88 libsystem_kernel.dylib`mach_msg + 20 frame #4: 0x00000001803c5ed8 CoreFoundation`__CFRunLoopServiceMachPort + 156 ... (lldb) up 4 frame #4: 0x00000001803c5ed8 CoreFoundation`__CFRunLoopServiceMachPort + 156 CoreFoundation`: -> 0x1803c5ed8 <+156>: mov x26, x0 0x1803c5edc <+160>: ldr x0, [x22] 0x1803c5ee0 <+164>: bl 0x1804f5080 ; symbol stub for: voucher_mach_msg_revert 0x1803c5ee4 <+168>: mov x0, x25 (lldb) expr -l swift -- $R0 (Signals.MainContainerViewController) $R1 = 0x0000000109f083a0 { UIKit.UIViewController = { ... } } The warning definitely has something to do with it (my exact warning is slightly different given I'm running the OSX 14 Beta): warning: Module "/usr/lib/system/libsystem_kernel.dylib" uses triple "arm64-apple-macosx14.0.0", which is not compatible with the target triple "arm64-apple-ios16.0.0-simulator". Enabling per-module Swift scratch context.