I have the same problem! In my case this always happened! Below the little part of log.
I have one MacBook Pro with Retina display, OS X El Capitan (10.11.4)
Process: ShareMail [2960]
Path: /System/Library/PrivateFrameworks/ShareKit.framework/Versions/A/PlugIns/ShareMa il.appex/Contents/MacOS/ShareMail
Identifier: ShareMail
Version: 1.0 (454.21)
Code Type: X86-64 (Native)
Parent Process: ??? [1]
Responsible: ShareMail [2960]
User ID: 501
Date/Time: 2016-04-03 21:15:11.824 -0300
OS Version: Mac OS X 10.11.4 (15E65)
Report Version: 11
Anonymous UUID: 375EBF3B-3A78-B272-0295-60940DB8C934
Time Awake Since Boot: 1800 seconds
System Integrity Protection: enabled
Crashed Thread: 0 Dispatch queue: com.apple.main-thread
Exception Type: EXC_BAD_INSTRUCTION (SIGILL)
Exception Codes: 0x0000000000000001, 0x0000000000000000
Exception Note: EXC_CORPSE_NOTIFY
Application Specific Information:
Configuration error: No SDK cache entry for extension!
Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0 libxpc.dylib 0x00007fff93902046 xpc_bundle_create_main + 442
1 libxpc.dylib 0x00007fff93901cdc xpc_main + 64
2 com.apple.Foundation 0x00007fff8db64bf3 -[NSXPCListener resume] + 160
3 com.apple.pluginkit.framework 0x00007fff90cb8e44 -[PKService run] + 493
4 com.apple.pluginkit.framework 0x00007fff90cb8b25 +[PKService main] + 55
5 com.apple.pluginkit.framework 0x00007fff90cb8e86 +[PKService _defaultRun:arguments:] + 17
6 libdyld.dylib 0x00007fff951a05ad start + 1
Thread 1:
0 libsystem_kernel.dylib 0x00007fff8b7305e2 __workq_kernreturn + 10
1 libsystem_pthread.dylib 0x00007fff9a5db578 _pthread_wqthread + 1283
2 libsystem_pthread.dylib 0x00007fff9a5d9341 start_wqthread + 13
Thread 2:: Dispatch queue: com.apple.libdispatch-manager
0 libsystem_kernel.dylib 0x00007fff8b730efa kevent_qos + 10
1 libdispatch.dylib 0x00007fff99b0b165 _dispatch_mgr_invoke + 216
2 libdispatch.dylib 0x00007fff99b0adcd _dispatch_mgr_thread + 52
is there any solution?