I also had this error on my system running Sierra 10.12.6 and the only recent change was the update to Safari 12.
Looking at the crash logs (In Console - User reports) certainly calls out the same things reported here as follows:
Process: | Spotlight [370] |
Path: | /System/Library/CoreServices/Spotlight.app/Contents/MacOS/Spotlight |
Identifier: | com.apple.Spotlight |
Version: | 1.0 (1075.40) |
Build Info: | SpotlightUI-1075040000000000~244 |
Code Type: | X86-64 (Native) |
Parent Process: | ??? [1] |
Responsible: | Spotlight [370] |
User ID: | 501 |
Date/Time: | 2018-09-26 08:59:32.454 -0500 |
OS Version: | Mac OS X 10.12.6 (16G1510) |
Report Version: | 12 |
Anonymous UUID: | 203C2CBC-8F7A-2B08-2B4D-E56DB6EF22CC |
Time Awake Since Boot: 120 seconds
System Integrity Protection: enabled
Crashed Thread: | 7 Dispatch queue: com.apple.root.default-qos |
Exception Type: | EXC_BAD_INSTRUCTION (SIGILL) |
Exception Codes: | 0x0000000000000001, 0x0000000000000000 |
Exception Note: | EXC_CORPSE_NOTIFY |
Termination Signal: | Illegal instruction: 4 |
Termination Reason: | Namespace SIGNAL, Code 0x4 |
Terminating Process: exc handler [0]
Application Specific Information:
XPC API Misuse: Release of last reference on a suspended connection.
Application Specific Signatures:
API Misuse
The important thing to note is what THREAD has crashed as seen below:
Thread 7 Crashed:: Dispatch queue: com.apple.root.default-qos
0 libxpc.dylib 0x00007fffd9152504 _xpc_api_misuse + 75
1 libxpc.dylib 0x00007fffd9141b7f _xpc_connection_last_xref_cancel + 52
2 libxpc.dylib 0x00007fffd9141b22 -[OS_xpc_connection _xref_dispose] + 17
3 com.apple.SafariServices.framework 0x00007fffc94c685f SSGetFullySimplifiedStringForURL + 746
4 com.apple.QuickLookUIFramework 0x00007fffc9203940 -[QLPreviewSchemeHandler_http _calculatePreviewURL:previewData:previewProperties:previewType:] + 331
5 com.apple.QuickLookUIFramework 0x00007fffc917d535 _QLPreviewItemGeneratorCopyPreviewUsingSchemeHandlerForURL + 158
6 com.apple.QuickLookFramework 0x00007fffc9483568 _QLPreviewReplyCreatedWithURL + 861
7 com.apple.QuickLookFramework 0x00007fffc9489e0e _XPreviewReplyCreatedWithURL + 219
8 com.apple.QuickLookFramework 0x00007fffc948a27e QLPreviewReply_server + 80
9 libsystem_kernel.dylib 0x00007fffd9014e0c mach_msg_server_once + 476
10 com.apple.QuickLookFramework 0x00007fffc9480d7f _QLPreviewWaitForPreviewTypeIfNecessary + 2631
11 com.apple.QuickLookFramework 0x00007fffc94801bc QLPreviewGetDisplayBundleID + 180
12 com.apple.QuickLookUIFramework 0x00007fffc9214a6f __65-[QLPreviewDocument startLoadingWithForcedDisplayBundleID:hints:]_block_invoke + 99
13 com.apple.QuickLookFramework 0x00007fffc94adfe4 QLTryCatchAndCrash(void () block_pointer) + 20
14 libdispatch.dylib 0x00007fffd8ec1524 _dispatch_call_block_and_release + 12
15 libdispatch.dylib 0x00007fffd8eb88fc _dispatch_client_callout + 8
16 libdispatch.dylib 0x00007fffd8ec7196 _dispatch_queue_override_invoke + 743
17 libdispatch.dylib 0x00007fffd8eba6b5 _dispatch_root_queue_drain + 476
18 libdispatch.dylib 0x00007fffd8eba48c _dispatch_worker_thread3 + 99
19 libsystem_pthread.dylib 0x00007fffd91075a2 _pthread_wqthread + 1299
20 libsystem_pthread.dylib 0x00007fffd910707d start_wqthread + 13
What this more or less tells me is that the Quicklook previewer is crashing when attempting to give you a preview of any weblink (in my case any *.webloc file).
What I had to do to fully fix this after trying all the normal things including rebuilding the spotlight index, trying safe mode, trying a new user, running disk check, checking the actual contents of the *.webloc files for corruption or malformed links, was to reinstall Sierra 10.12.6 by shutting down my system and holding COMMAND +R to "internet recovery" the OS on my machine.
Once the OS was reinstalled, full functionality was restored and I can now use spotlight as normal and include all items in the results with no further issues.