To reproduce:
1. Open any project
2. Import user's attached FBX file

Expected: editor doesn't crash
Actual: editor crashes

Reproduced in: 2017.1.3p1, 2017.2.1p3, 2017.3.1f1, 2018.1.0b6

Note: alternative stack trace when ending task via task manager:
"0x00007FFCBA22A25D (mono) [c:\buildslave\mono\build\mono\mini\mini-exceptions.c:218] find_jit_info_no_ext
0x00007FFCBA22A3EA (mono) [c:\buildslave\mono\build\mono\mini\mini-exceptions.c:287] mono_find_jit_info
0x00007FFCBA22A87F (mono) [c:\buildslave\mono\build\mono\mini\mini-exceptions.c:686] mono_jit_walk_stack_from_ctx
0x00007FFCBA1582BE (mono) [c:\buildslave\mono\build\mono\metadata\loader.c:2077] mono_method_get_last_managed
0x0000000141176BA6 (Unity) ExtractMonoStacktrace
0x000000014108C3D2 (Unity) DebugStringToFile
0x000000014108CA1C (Unity) DebugStringToFile
0x00000001408E83F4 (Unity) CrashedAssetImportsDatabase::NotifyRefreshComplete
0x000000014091C55B (Unity) AssetInterface::Refresh
0x00000001408C7C43 (Unity) AssetDatabase::RefreshAndSaveAssets
0x000000014014560C (Unity) Application::CoreShutdown
0x00000001401484F9 (Unity) Application::Terminate
0x0000000140029ADC (Unity) ContainerWindow::ContainerWndProc
0x00007FFCEC64B85D (USER32) CallWindowProcW
0x00007FFCEC64B54C (USER32) CallWindowProcW
0x00007FFCEC6619C3 (USER32) GetTopWindow
0x00007FFCEE093B44 (ntdll) KiUserCallbackDispatcher
0x00007FFCEAF41164 (win32u) NtUserMessageCall
0x00007FFCEC649F52 (USER32) GetWindowTextW
0x00007FFCEC649782 (USER32) ClientToScreen
0x00007FFCE7CC4202 (uxtheme) Ordinal119
0x00007FFCE7CC2022 (uxtheme) GetThemeEnumValue
0x00007FFCE7CCB5EE (uxtheme) Ordinal119
0x00007FFCE7CC9EA1 (uxtheme) Ordinal119
0x00007FFCEC649C97 (USER32) GetWindowTextW
0x0000000140029F95 (Unity) ContainerWindow::ContainerWndProc
0x00007FFCEC64B85D (USER32) CallWindowProcW
0x00007FFCEC64B54C (USER32) CallWindowProcW
0x00007FFCEC6619C3 (USER32) GetTopWindow
0x00007FFCEE093B44 (ntdll) KiUserCallbackDispatcher
0x00007FFCEAF41164 (win32u) NtUserMessageCall
0x00007FFCEC649F52 (USER32) GetWindowTextW
0x00007FFCEC649782 (USER32) ClientToScreen
0x00007FFCE7CC4202 (uxtheme) Ordinal119
0x00007FFCE7CC1FD7 (uxtheme) GetThemeEnumValue
0x00007FFCE7CCB5EE (uxtheme) Ordinal119
0x00007FFCE7CC9EA1 (uxtheme) Ordinal119
0x00007FFCEC649C97 (USER32) GetWindowTextW
0x0000000140029F95 (Unity) ContainerWindow::ContainerWndProc
0x00007FFCEC64B85D (USER32) CallWindowProcW
0x00007FFCEC64B1EF (USER32) DispatchMessageW
0x0000000141AA44BA (Unity) MainMessageLoop
0x0000000141AA5E2E (Unity) WinMain
0x0000000141D0AFAC (Unity) __tmainCRTStartup
0x00007FFCEB781FE4 (KERNEL32) BaseThreadInitThunk
0x00007FFCEE05EFB1 (ntdll) RtlUserThreadStart"