Mail crash when changing setting for BCC

I get the following error when trying to change the setting for BCC, with a new message window open and selected.
It says: Mail quit unexpectedly while using the HockeySDK plug-in.
Not sure if this is related to SpamSieve or anther Mail add-on program on my Mac. I have a MacBook Pro 13", 2016, 2.9 GHz, running Sierra 10.12.6
The other Mail add-on I have loaded is Mail Butler.
Part of the Problem details are copied below.
Jason

Process: Mail [26172]
Path: /Applications/Mail.app/Contents/MacOS/Mail
Identifier: com.apple.mail
Version: 10.3 (3273)
Build Info: Mail-3273000000000000~4
Code Type: X86-64 (Native)
Parent Process: ??? [1]
Responsible: Mail [26172]
User ID: 501

PlugIn Path: /Users/USER/Library/Mail/*/HockeySDK.framework/Versions/A/HockeySDK
PlugIn Identifier: net.hockeyapp.sdk.mac
PlugIn Version: 4.1.3 (60)

Date/Time: 2018-02-12 16:17:44.247 -0500
OS Version: Mac OS X 10.12.6 (16G1114)
Report Version: 12
Anonymous UUID: 4A4BBCC2-81E9-8A8E-4A07-D24F6D070509

Sleep/Wake UUID: 4A818FA5-437C-46DD-BDD4-8ED46B67FC2D

Time Awake Since Boot: 280000 seconds
Time Since Wake: 6800 seconds

System Integrity Protection: enabled

Crashed Thread: 0 Dispatch queue: com.apple.main-thread

Exception Type: EXC_CRASH (SIGABRT)
Exception Codes: 0x0000000000000000, 0x0000000000000000
Exception Note: EXC_CORPSE_NOTIFY

Application Specific Information:
abort() called

Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0 libsystem_kernel.dylib 0x00007fffe593fd42 __pthread_kill + 10
1 libsystem_pthread.dylib 0x00007fffe5a2d457 pthread_kill + 90
2 libsystem_c.dylib 0x00007fffe58a5420 abort + 129
3 net.hockeyapp.sdk.mac 0x000000010d0681d3 uncaught_exception_handler + 27
4 com.apple.HIToolbox 0x00007fffcf5c4b4d DispatchEventToHandlers(EventTargetRec*, OpaqueEventRef*, HandlerCallRec*) + 1140
5 com.apple.HIToolbox 0x00007fffcf5c3ff6 SendEventToEventTargetInternal(OpaqueEventRef*, OpaqueEventTargetRef*, HandlerCallRec*) + 428
6 com.apple.HIToolbox 0x00007fffcf5d9d14 SendEventToEventTarget + 40
7 com.apple.HIToolbox 0x00007fffcf6263e6 SendHICommandEvent(unsigned int, HICommand const*, unsigned int, unsigned int, unsigned char, void const*, OpaqueEventTargetRef*, OpaqueEventTargetRef*, OpaqueEventRef**) + 411
8 com.apple.HIToolbox 0x00007fffcf6519fb SendMenuCommandWithContextAndModifiers + 59
9 com.apple.HIToolbox 0x00007fffcf6519aa SendMenuItemSelectedEvent + 188
10 com.apple.HIToolbox 0x00007fffcf65187d FinishMenuSelection(SelectionData*, MenuResult*, MenuResult*) + 96
11 com.apple.HIToolbox 0x00007fffcf6522b7 MenuSelectCore(MenuData*, Point, double, unsigned int, OpaqueMenuRef**, unsigned short*) + 702
12 com.apple.HIToolbox 0x00007fffcf651f66 _HandleMenuSelection2 + 460
13 com.apple.AppKit 0x00007fffcdd04368 _NSHandleCarbonMenuEvent + 239
14 com.apple.AppKit 0x00007fffcdf7e702 _DPSEventHandledByCarbon + 54
15 com.apple.AppKit 0x00007fffce2ff0c5 -[NSApplication(NSEvent) _nextEventMatchingEventMask:untilDate:inMode:dequeue:] + 963
16 com.apple.AppKit 0x00007fffcdb783db -[NSApplication run] + 926
17 com.apple.AppKit 0x00007fffcdb42e0e NSApplicationMain + 1237
18 libdyld.dylib 0x00007fffe5811235 start + 1

Thread 1:
0 libsystem_kernel.dylib 0x00007fffe593fbf2 __psynch_cvwait + 10
1 libsystem_pthread.dylib 0x00007fffe5a2b7fa _pthread_cond_wait + 712
2 libc++.1.dylib 0x00007fffe43a94cd std::__1::condition_variable::wait(std::__1::unique_lock<std::__1::mutex>&) + 47
3 com.apple.JavaScriptCore 0x00007fffd309a43c void std::__1::condition_variable_any::wait<std::__1::unique_lock<bmalloc::Mutex> >(std::__1::unique_lock<bmalloc::Mutex>&) + 108
4 com.apple.JavaScriptCore 0x00007fffd309a3bb bmalloc::AsyncTask<bmalloc::Heap, void (bmalloc::Heap::)()>::threadRunLoop() + 155
5 com.apple.JavaScriptCore 0x00007fffd309a28d bmalloc::AsyncTask<bmalloc::Heap, void (bmalloc::Heap::
)()>::threadEntryPoint(bmalloc::AsyncTask<bmalloc::Heap, void (bmalloc::Heap::)()>) + 29
6 com.apple.JavaScriptCore 0x00007fffd309a53d void* std::__1::__thread_proxy<std::__1::tuple<void ()(bmalloc::AsyncTask<bmalloc::Heap, void (bmalloc::Heap::)()>), bmalloc::AsyncTask<bmalloc::Heap, void (bmalloc::Heap::)()>> >(void) + 93
7 libsystem_pthread.dylib 0x00007fffe5a2a93b _pthread_body + 180
8 libsystem_pthread.dylib 0x00007fffe5a2a887 _pthread_start + 286
9 libsystem_pthread.dylib 0x00007fffe5a2a08d thread_start + 13

Thread 2:: com.apple.NSURLConnectionLoader
0 libsystem_kernel.dylib 0x00007fffe593834a mach_msg_trap + 10
1 libsystem_kernel.dylib 0x00007fffe5937797 mach_msg + 55
2 com.apple.CoreFoundation 0x00007fffd008d434 __CFRunLoopServiceMachPort + 212
3 com.apple.CoreFoundation 0x00007fffd008c8c1 __CFRunLoopRun + 1361
4 com.apple.CoreFoundation 0x00007fffd008c114 CFRunLoopRunSpecific + 420
5 com.apple.CFNetwork 0x00007fffcf1c8344 +[NSURLConnection(Loader) _resourceLoadLoop:] + 313
6 com.apple.Foundation 0x00007fffd1aaf8ad NSThread__start + 1243
7 libsystem_pthread.dylib 0x00007fffe5a2a93b _pthread_body + 180
8 libsystem_pthread.dylib 0x00007fffe5a2a887 _pthread_start + 286
9 libsystem_pthread.dylib 0x00007fffe5a2a08d thread_start + 13

Thread 3:: com.apple.CFSocket.private
0 libsystem_kernel.dylib 0x00007fffe593feb6 __select + 10
1 com.apple.CoreFoundation 0x00007fffd00c866a __CFSocketManager + 682
2 libsystem_pthread.dylib 0x00007fffe5a2a93b _pthread_body + 180
3 libsystem_pthread.dylib 0x00007fffe5a2a887 _pthread_start + 286
4 libsystem_pthread.dylib 0x00007fffe5a2a08d thread_start + 13

Thread 4:
0 libsystem_kernel.dylib 0x00007fffe593834a mach_msg_trap + 10
1 libsystem_kernel.dylib 0x00007fffe5937797 mach_msg + 55
2 net.hockeyapp.sdk.mac 0x000000010d07204e exception_server_thread + 201
3 libsystem_pthread.dylib 0x00007fffe5a2a93b _pthread_body + 180
4 libsystem_pthread.dylib 0x00007fffe5a2a887 _pthread_start + 286
5 libsystem_pthread.dylib 0x00007fffe5a2a08d thread_start + 13

Thread 5:: com.apple.coreanimation.render-server
0 libsystem_kernel.dylib 0x00007fffe593834a mach_msg_trap + 10
1 libsystem_kernel.dylib 0x00007fffe5937797 mach_msg + 55
2 com.apple.QuartzCore 0x00007fffd5c70bd4 CA::Render::Server::server_thread(void*) + 272
3 com.apple.QuartzCore 0x00007fffd5d213ab thread_fun + 25
4 libsystem_pthread.dylib 0x00007fffe5a2a93b _pthread_body + 180
5 libsystem_pthread.dylib 0x00007fffe5a2a887 _pthread_start + 286
6 libsystem_pthread.dylib 0x00007fffe5a2a08d thread_start + 13

Thread 6:: com.apple.NSEventThread
0 libsystem_kernel.dylib 0x00007fffe593834a mach_msg_trap + 10
1 libsystem_kernel.dylib 0x00007fffe5937797 mach_msg + 55
2 com.apple.CoreFoundation 0x00007fffd008d434 __CFRunLoopServiceMachPort + 212
3 com.apple.CoreFoundation 0x00007fffd008c8c1 __CFRunLoopRun + 1361
4 com.apple.CoreFoundation 0x00007fffd008c114 CFRunLoopRunSpecific + 420
5 com.apple.AppKit 0x00007fffcdcd0f02 _NSEventThread + 205
6 libsystem_pthread.dylib 0x00007fffe5a2a93b _pthread_body + 180
7 libsystem_pthread.dylib 0x00007fffe5a2a887 _pthread_start + 286
8 libsystem_pthread.dylib 0x00007fffe5a2a08d thread_start + 13

Thread 7:
0 libsystem_kernel.dylib 0x00007fffe594044e __workq_kernreturn + 10
1 libsystem_pthread.dylib 0x00007fffe5a2a621 _pthread_wqthread + 1426
2 libsystem_pthread.dylib 0x00007fffe5a2a07d start_wqthread + 13

Thread 8:
0 libsystem_kernel.dylib 0x00007fffe594044e __workq_kernreturn + 10
1 libsystem_pthread.dylib 0x00007fffe5a2a621 _pthread_wqthread + 1426
2 libsystem_pthread.dylib 0x00007fffe5a2a07d start_wqthread + 13

Thread 9:
0 libsystem_kernel.dylib 0x00007fffe594044e __workq_kernreturn + 10
1 libsystem_pthread.dylib 0x00007fffe5a2a48e _pthread_wqthread + 1023
2 libsystem_pthread.dylib 0x00007fffe5a2a07d start_wqthread + 13

Thread 10:
0 libsystem_kernel.dylib 0x00007fffe594044e __workq_kernreturn + 10
1 libsystem_pthread.dylib 0x00007fffe5a2a621 _pthread_wqthread + 1426
2 libsystem_pthread.dylib 0x00007fffe5a2a07d start_wqthread + 13

Thread 0 crashed with X86 Thread State (64-bit):
rax: 0x0000000000000000 rbx: 0x0000000000000006 rcx: 0x00007fff587e3e98 rdx: 0x0000000000000000
rdi: 0x0000000000000307 rsi: 0x0000000000000006 rbp: 0x00007fff587e3ec0 rsp: 0x00007fff587e3e98
r8: 0x0000000000000010 r9: 0x00007fff587e3cd8 r10: 0x0000000008000000 r11: 0x0000000000000206
r12: 0x0000000000000000 r13: 0x0000000000000000 r14: 0x00007fffee72f3c0 r15: 0x00006000000990f0
rip: 0x00007fffe593fd42 rfl: 0x0000000000000206 cr2: 0x0000000126ce5674

Logical CPU: 0
Error Code: 0x020000b8
Trap Number: 133

Binary Images:
0x10741b000 - 0x1077feff7 com.apple.mail (10.3 - 3273) <E989542D-BFD1-351A-BB3A-B30C11E96019> /Applications/Mail.app/Contents/MacOS/Mail
0x10b7d9000 - 0x10b805fff +com.c-command.spamsieve.mailplugin (2.9.30 - 2.9.30) <E55F6E9B-5C05-3E02-B670-D925F80A18A5> /Users/USER/Library/Mail//SpamSieve
0x10ba56000 - 0x10ba57fff com.apple.AddressBook.LocalSourceBundle (10.0 - 1756.20) <68DF13B0-DA0C-3983-A53A-0D05F22BC5FD> /System/Library/Address Book Plug-Ins/LocalSource.sourcebundle/Contents/MacOS/LocalSource
0x10ba76000 - 0x10ba80fff com.apple.SyncedDefaults (2.0 - 261.4) <DF17161D-B219-3D1A-978E-95E054AB37D9> /System/Library/PrivateFrameworks/SyncedDefaults.framework/SyncedDefaults
0x10ba9b000 - 0x10ba9ffff com.apple.DirectoryServicesSource (10.0 - 1756.20) <0F7DD576-8D58-3330-97F1-28FAB60043B5> /System/Library/Address Book Plug-Ins/DirectoryServices.sourcebundle/Contents/MacOS/DirectoryServices
0x10c5b6000 - 0x10c5b8fff apop.so (192) <4A9EB9B8-566C-325B-A685-C207B21F21C8> /usr/lib/sasl2/apop.so
0x10c5bd000 - 0x10c5befff atoken.so (192) <341FB1D5-DF5F-365E-82BE-08F141F69A1A> /usr/lib/sasl2/atoken.so
0x10c5c3000 - 0x10c5d3ff7 dhx.so (192) <86063B99-0D2B-3CFE-9F75-323906C87366> /usr/lib/sasl2/dhx.so
0x10c5e1000 - 0x10c5eaff7 digestmd5WebDAV.so (192) <932D88F3-C5BC-340B-A3FA-38121114136C> /usr/lib/sasl2/digestmd5WebDAV.so
0x10c5f0000 - 0x10c5f2fff libanonymous.2.so (209) <3CD8B7D8-5B20-339C-99C4-FA7986F95683> /usr/lib/sasl2/libanonymous.2.so
0x10c5f7000 - 0x10c5f8fff plain-clienttoken.so (192) <D7A44A21-93A3-3603-9522-82EA7D3CA127> /usr/lib/sasl2/plain-clienttoken.so
0x10c64d000 - 0x10c798ff3 +com.feingeist.MailButler (6901 - 6901) <0AED428C-1B48-381E-B7ED-4748C615FB98> /Users/USER/Library/Mail/
/MailButler
0x10c912000 - 0x10c934ff7 +com.deusty.CocoaLumberjack (2.1.0 - 1) <6415EDF9-63A9-3F65-BE7B-7E43365C7B79> /Users/USER/Library/Mail//CocoaLumberjack.framework/Versions/A/CocoaLumberjack
0x10c951000 - 0x10cae6ff7 +com.dropbox.ObjectiveDropboxOfficial (3.0.18 - 1) <D9310C8D-79CD-3082-86A9-E1BA88DEDAFC> /Users/USER/Library/Mail/
/ObjectiveDropboxOfficial.framework/Versions/A/ObjectiveDropboxOfficial
0x10cc98000 - 0x10ccbcfff +com.dlsxtreme.connection (1.0) <54ED93B5-6C9D-31B4-B443-7DD0B688F97D> /Users/USER/Library/Mail//ConnectionKit.framework/Versions/A/ConnectionKit
0x10ccdc000 - 0x10cd24ffb +com.google.GTL (2.0) <420A595B-9DD7-31E8-82F7-385854BB569A> /Users/USER/Library/Mail/
/GTL.framework/Versions/A/GTL
0x10cd47000 - 0x10cee1ff7 +com.evernote.EvernoteSDK-Mac (1.0 - 1) <E657C6B7-7A0A-3E03-BF9E-A3AB2DBB9F34> /Users/USER/Library/Mail//EvernoteSDK-Mac.framework/Versions/A/EvernoteSDK-Mac
0x10d00a000 - 0x10d01dff7 +com.kulakov.ShortcutRecorder (2.14) <126DC4B4-4A13-350D-9C79-D1E3DC0DA8A8> /Users/USER/Library/Mail/
/ShortcutRecorder.framework/Versions/A/ShortcutRecorder
0x10d02e000 - 0x10d0acfff +net.hockeyapp.sdk.mac (4.1.3 - 60) <36DD6A34-FE99-373D-9F89-2AE75630A492> /Users/USER/Library/Mail//HockeySDK.framework/Versions/A/HockeySDK
0x10d109000 - 0x10d110ff7 +com.kulakov.PTHotKey (1.4) <2AADF604-65A6-3AF4-9873-F1B00A27A56E> /Users/USER/Library/Mail/
/PTHotKey.framework/Versions/A/PTHotKey
0x10d11b000 - 0x10d13cfff +com.alamofire.AFNetworking (3.0.0 - 3.1.0) <363F3F33-8379-3EAB-8652-7F65B12F386B> /Users/USER/Library/Mail//AFNetworking.framework/Versions/A/AFNetworking
0x10d15e000 - 0x10d170fff +com.karelia.CURLHandle (1.0) <4223B644-60EA-3390-97A3-0EF154A04F3B> /Users/USER/Library/Mail/
/ConnectionKit.framework/Versions/A/Frameworks/CURLHandle.framework/Versions/A/CURLHandle
0x10d184000 - 0x10d192fff +com.MattRajca.DAVKit (1.0 - 1) <F5E6B1E9-1347-36F2-B079-DE925EA12BDF> /Users/USER/Library/Mail//ConnectionKit.framework/Versions/A/Frameworks/DAVKit.framework/Versions/A/DAVKit
0x10d1a2000 - 0x10d1f9fff +libcurl.dylib (8) <99C4B91C-DA8F-334D-9BAC-0542510EE006> /Users/USER/Library/Mail/
/ConnectionKit.framework/Versions/A/Frameworks/CURLHandle.framework/Versions/A/Frameworks/libcurl.dylib
0x10d20b000 - 0x10d217ff7 +libcares.dylib (4) <1F76A182-D7C9-3EE7-827D-BA4956D11A6B> /Users/USER/Library/Mail//ConnectionKit.framework/Versions/A/Frameworks/CURLHandle.framework/Versions/A/Frameworks/libcares.dylib
0x10d21e000 - 0x10d252ff7 +libssh2.dylib (2.1) <C07E1D87-33F6-3C20-AAA1-5C15EB98B942> /Users/USER/Library/Mail/
/ConnectionKit.framework/Versions/A/Frameworks/CURLHandle.framework/Versions/A/Frameworks/libssh2.dylib
0x10d25b000 - 0x10d2aaff7 +libssl.dylib (1) <4A013C10-0521-3DE5-A81C-34213061FC57> /Users/USER/Library/Mail//ConnectionKit.framework/Versions/A/Frameworks/CURLHandle.framework/Versions/A/Frameworks/libssl.dylib
0x10d2ca000 - 0x10d47502f +libcrypto.dylib (1) <3696EB1B-67E1-3F49-B586-BBA8A3382A83> /Users/USER/Library/Mail/
/ConnectionKit.framework/Versions/A/Frameworks/CURLHandle.framework/Versions/A/Frameworks/libcrypto.dylib
0x10d7d5000 - 0x10d7d7ff3 libcrammd5.2.so (209) <41B64B45-0D07-3068-B5A1-F7F6DBE8BC8C> /usr/lib/sasl2/libcrammd5.2.so
0x10d7dc000 - 0x10d7e5ff3 libdigestmd5.2.so (209) <AA60D907-A450-30EF-ACE8-DC573CE8BD21> /usr/lib/sasl2/libdigestmd5.2.so
0x10d7eb000 - 0x10d7f0ffb libgssapiv2.2.0.18.so (209) <D04D91A6-0197-38A9-AB02-5D8D4B6044B2>

External Modification Summary:
Calls made by other processes targeting this process:
task_for_pid: 57
thread_create: 0
thread_set_state: 0
Calls made by this process:
task_for_pid: 0
thread_create: 0
thread_set_state: 0
Calls made by all processes on this machine:
task_for_pid: 9918719
thread_create: 0
thread_set_state: 0

VM Region Summary:
ReadOnly portion of Libraries: Total=414.7M resident=0K(0%) swapped_out_or_unallocated=414.7M(100%)
Writable regions: Total=1.3G written=0K(0%) resident=0K(0%) swapped_out=0K(0%) unallocated=1.3G(100%)

                              VIRTUAL   REGION 

REGION TYPE SIZE COUNT (non-coalesced)
=========== ======= =======
Accelerate framework 512K 5
Activity Tracing 256K 2
CG backing stores 1712K 20
CG image 2964K 252
CoreAnimation 18.2M 284
CoreData Object IDs 4100K 3
CoreImage 232K 26
CoreUI image data 3752K 44
CoreUI image file 252K 12
Foundation 32K 3
Image IO 76K 15
JS JIT generated code 128.0M 4
JS JIT generated code (reserved) 896.0M 2 reserved VM address space (unallocated)
Kernel Alloc Once 8K 2
MALLOC 213.8M 65
MALLOC guard page 48K 10
Memory Tag 242 12K 2
Memory Tag 251 164K 6
OpenCL 16K 3
SQLite page cache 5952K 28
STACK GUARD 56.0M 12
Stack 13.1M 12
VM_ALLOCATE 624K 75
WebKit Malloc 18.1M 40
__DATA 49.0M 454
__GLSLBUILTINS 2588K 2
__IMAGE 528K 2
__LINKEDIT 121.8M 56
__TEXT 292.9M 451
__UNICODE 556K 2
mapped file 214.1M 171
shared memory 16.4M 13
=========== ======= =======
TOTAL 2.0G 2046
TOTAL, minus reserved VM space 1.1G 2046

Model: MacBookPro13,2, BootROM MBP132.0233.B00, 2 processors, Intel Core i5, 2.9 GHz, 8 GB, SMC 2.37f20
Graphics: Intel Iris Graphics 550, Intel Iris Graphics 550, Built-In
Memory Module: BANK 0/DIMM0, 4 GB, LPDDR3, 2133 MHz, 0x802C, 0x4D5435324C3531324D3332443250462D3039
Memory Module: BANK 1/DIMM0, 4 GB, LPDDR3, 2133 MHz, 0x802C, 0x4D5435324C3531324D3332443250462D3039
AirPort: spairport_wireless_card_type_airport_extreme (0x14E4, 0x157), Broadcom BCM43xx 1.0 (7.21.171.133.1a2)
Bluetooth: Version 5.0.5f1, 3 services, 27 devices, 1 incoming serial ports
Network Service: USB 10/100/1000 LAN 2, Ethernet, en8
USB Device: USB 3.0 Bus
USB Device: USB2.0 Hub
USB Device: USB Receiver
USB Device: iBridge
USB Device: USB3.0 Hub
USB Device: USB 10/100/1000 LAN
Thunderbolt Bus: MacBook Pro, Apple Inc., 22.1
Thunderbolt Bus: MacBook Pro, Apple Inc., 22.1

Probably another plug-in, since SpamSieve does not use HockeySDK.