Xojo 2026 r1.2, Mac OS Sequoia.
I clicked on a button in my UI which has worked without issue for ages and my app beachballed, with Xojo eventually providing this crash report (abridged).
Any ideas what happened?
Code Type: ARM-64 (Native)
Parent Process: launchd [1]
User ID: 501
Date/Time: 2026-07-19 12:01:11.4261 -0400
OS Version: macOS 15.7.5 (24G624)
Report Version: 12
Anonymous UUID: BF1976E1-A18B-5301-8389-0B623F6C90D2
Sleep/Wake UUID: FCCD4781-755A-449B-ACEA-56FA49608FB4
Time Awake Since Boot: 2500000 seconds
Time Since Wake: 69011 seconds
System Integrity Protection: enabled
Crashed Thread: 0 Dispatch queue: com.apple.main-thread
Exception Type: EXC_BREAKPOINT (SIGKILL)
Exception Codes: 0x0000000000000001, 0x0000000194be4cd8
Termination Reason: Namespace FOUNDATION, Code 1
Application Specific Information:
BUG IN CLIENT OF LIBPLATFORM: Trying to recursively lock an os_unfair_lock
Abort Cause 259
abort() called
Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0 libsystem_platform.dylib 0x194be4cd8 _os_unfair_lock_recursive_abort + 36
1 libsystem_platform.dylib 0x194bdf400 _os_unfair_lock_lock_slow + 300
2 libsystem_malloc.dylib 0x1949a8d34 tiny_malloc_should_clear + 128
3 libsystem_malloc.dylib 0x1949a7be8 szone_malloc_should_clear + 84
4 libc++abi.dylib 0x194b613e0 operator new(unsigned long) + 52
5 libc++.1.dylib 0x194acf5f4 std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>>::__grow_by_and_replace(unsigned long, unsigned long, unsigned long, unsigned long, unsigned long, unsigned long, char const*) + 164
6 libc++.1.dylib 0x194ad01e4 std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>>::append(char const*, unsigned long) + 108
7 XojoFramework 0x106422ee8 DebuggerPacketBuilder::AddInt64(long long) + 120
8 XojoFramework 0x10642e918 0x1062a0000 + 1632536
9 XojoFramework 0x106543b38 0x1062a0000 + 2767672
10 XojoFramework 0x106543ae4 StackContext::Crawl(StackBounds, std::__1::function<bool (long, long)>) const + 120
11 XojoFramework 0x106427bdc 0x1062a0000 + 1604572
12 XojoFramework 0x106424074 0x1062a0000 + 1589364
13 XojoFramework 0x106423670 DSDelegate::DebuggerConnectionMessage(DebuggerPacketParser const&) + 24
14 XojoFramework 0x1064217b8 DebuggerConnection::ProcessMessage(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>>) + 140
15 XojoFramework 0x1064f6468 TCPSocketConnection::SocketDataReceived(TCPSocket*) + 268
16 XojoFramework 0x1063b1084 TCPSocket::FireEvents() + 192
17 XojoFramework 0x1063ae20c TCPSocketPosix::Poll() + 1036
18 XojoFramework 0x10642690c 0x1062a0000 + 1599756
19 XojoFramework 0x10642e72c 0x1062a0000 + 1632044
20 XojoFramework 0x1064313d8 0x1062a0000 + 1643480
21 libsystem_platform.dylib 0x194be16a4 _sigtramp + 56
22 libsystem_pthread.dylib 0x194ba7848 pthread_kill + 296
23 libsystem_c.dylib 0x194ab0a2c abort + 124
24 libsystem_malloc.dylib 0x1949b4174 malloc_vreport + 892
25 libsystem_malloc.dylib 0x1949df954 malloc_zone_error + 100
26 libsystem_malloc.dylib 0x1949df6c4 _tiny_check_and_zero_inline_meta_from_freelist + 188
27 libsystem_malloc.dylib 0x1949a96c8 tiny_malloc_from_free_list + 420
28 libsystem_malloc.dylib 0x1949a8dc4 tiny_malloc_should_clear + 272
29 libsystem_malloc.dylib 0x1949a7be8 szone_malloc_should_clear + 84
30 libobjc.A.dylib 0x1947b37ec class_createInstance + 76
31 Foundation 0x19620a0ac NSAllocateObject + 28
32 Foundation 0x19620d6d0 +[NSPathStore2 pathStoreWithCharacters:length:] + 68
33 Foundation 0x1962122c0 -[NSString(NSPathUtilities) stringByAppendingPathComponent:] + 576
34 AppKit 0x1994350d8 +[NSBundle(NSNibLoadingInternal) _nibFileToLoadFromListOfFiles:atNibPath:isKeyed:] + 96
35 AppKit 0x198b889ac +[NSBundle(NSNibLoading) _loadNibFile:nameTable:options:withZone:ownerBundle:] + 1024
36 AppKit 0x198d13d60 -[NSWindowController loadWindow] + 300
37 AppKit 0x198d13b18 -[NSWindowController window] + 80
38 XojoFramework 0x106540aec 0x1062a0000 + 2755308
39 XojoFramework 0x1063a13b8 TooltipImpCocoa::~TooltipImpCocoa() + 36
40 XojoFramework 0x1063a13e4 TooltipImpCocoa::~TooltipImpCocoa() + 12
41 XojoFramework 0x10648a988 RuntimeListbox::~RuntimeListbox() + 104
42 XojoFramework 0x10634d318 CocoaListbox::~CocoaListbox() + 12
43 XojoFramework 0x106539cc4 SubPane::Unlock() + 252
44 XojoFramework 0x106539c28 SubPane::Unlock() + 96
45 XojoFramework 0x106539c28 SubPane::Unlock() + 96
46 XojoFramework 0x1064e4300 RuntimeCustomControlPane::UnprotectCausesDeath() + 108
47 XojoFramework 0x10638a2d8 0x1062a0000 + 959192
48 AppearancePakCocoa.dylib 0x10627f9ec 0x106278000 + 31212
49 AppKit 0x199775fe0 _routeMouseUpEvent + 132
50 AppKit 0x198cd7c20 -[NSWindow(NSEventRouting) _reallySendEvent:isDelayedEvent:] + 440
51 AppKit 0x198cd78a0 -[NSWindow(NSEventRouting) sendEvent:] + 288
52 XojoFramework 0x106386f14 0x1062a0000 + 945940
53 AppKit 0x19954f34c -[NSApplication(NSEventRouting) sendEvent:] + 1504
54 XojoFramework 0x106378fb0 0x1062a0000 + 888752
55 Production Test Information Manager.debug 0x10458af70 Application._CallFunctionWithExceptionHandling%%o<Application>p + 164
56 XojoFramework 0x1064f5464 CallFunctionWithExceptionHandling(void (*)()) + 180
57 XojoFramework 0x106378f68 0x1062a0000 + 888680
58 AppKit 0x19914e42c -[NSApplication _handleEvent:] + 60
59 AppKit 0x198ba4c0c -[NSApplication run] + 520
60 XojoFramework 0x1064f3c98 RuntimeRun + 48
61 Production Test Information Manager.debug 0x1047047c4 REALbasic._RuntimeRun + 28
62 Production Test Information Manager.debug 0x104d89ba4 _Main + 632
63 Production Test Information Manager.debug 0x104d857f4 main + 36
64 dyld 0x194806b98 start + 6076
Thread 1:: com.apple.NSEventThread
0 libsystem_kernel.dylib 0x194b65c34 mach_msg2_trap + 8
1 libsystem_kernel.dylib 0x194b78338 mach_msg2_internal + 76
2 libsystem_kernel.dylib 0x194b6e764 mach_msg_overwrite + 484
3 libsystem_kernel.dylib 0x194b65fa8 mach_msg + 24
4 CoreFoundation 0x194c92c0c __CFRunLoopServiceMachPort + 160
5 CoreFoundation 0x194c91528 __CFRunLoopRun + 1208
6 CoreFoundation 0x194c909e8 CFRunLoopRunSpecific + 572
7 AppKit 0x198cd578c _NSEventThread + 140
8 libsystem_pthread.dylib 0x194ba7bc8 _pthread_start + 136
9 libsystem_pthread.dylib 0x194ba2b80 thread_start + 8
Thread 2:: HIE: M_ d3ba3c02f5bc2078 2026-07-13 13:20:00.951
0 libsystem_kernel.dylib 0x194b65c34 mach_msg2_trap + 8
1 libsystem_kernel.dylib 0x194b78338 mach_msg2_internal + 76
2 libsystem_kernel.dylib 0x194b9581c thread_suspend + 108
3 HIServices 0x19ba23504 SOME_OTHER_THREAD_SWALLOWED_AT_LEAST_ONE_EXCEPTION + 20
4 Foundation 0x19625aba8 __NSThread__start__ + 732
5 libsystem_pthread.dylib 0x194ba7bc8 _pthread_start + 136
6 libsystem_pthread.dylib 0x194ba2b80 thread_start + 8
Thread 3:
0 libsystem_pthread.dylib 0x194ba2b6c start_wqthread + 0
Thread 4:
0 libsystem_pthread.dylib 0x194ba2b6c start_wqthread + 0
Thread 5:
0 libsystem_pthread.dylib 0x194ba2b6c start_wqthread + 0
Thread 6:
0 libsystem_pthread.dylib 0x194ba2b6c start_wqthread + 0
Thread 0 crashed with ARM Thread State (64-bit):
x0: 0x0000000000000103 x1: 0x0000000000050000 x2: 0x0000000000000000 x3: 0x0000000000000103
x4: 0x0000000000000088 x5: 0x0000000000000000 x6: 0x0000000000000011 x7: 0x000000016baebca0
x8: 0x0000000000000103 x9: 0x0000000000000001 x10: 0x0000000000000002 x11: 0x0000000000000120
x12: 0x0000000000000017 x13: 0x00000000000007fd x14: 0x000000009e23406d x15: 0x000000009e033847
x16: 0x0000000194bde860 x17: 0x0000000203b9f790 x18: 0x0000000000000000 x19: 0x0000000000000103
x20: 0x0000000000050000 x21: 0x0000000000000000 x22: 0x000000010530d000 x23: 0x0000000000000103
x24: 0x0000000000000000 x25: 0x0000000001000002 x26: 0x0000000000000103 x27: 0x0000000202b46240
x28: 0x0000000202b46320 fp: 0x000000016baebaf0 lr: 0x0000000194bdf400
sp: 0x000000016baebab0 pc: 0x0000000194be4cd8 cpsr: 0x20001000
far: 0x0000000000000000 esr: 0xf200b001 (Breakpoint) brk 45057