Photos App won't open on MacOS Mojave 10.14.4

Found this from "Old Toad" and it appears to have worked:

Try the following:

1 - launch Photos with the Option key held down and create a new, test library.

2 - import a couple of photos into it and open and close a couple of times.

3 - now try to open your original library.

For some reason this has helped some users to open a library that wouldn't open previously. Maybe a bad preference files or cache file. Worth a try and keep your fingers:

Code from "Photos quit unexpectedly" report (unfortunately I don't know enough to know what any of this means):

Process: Photos [781]

Path: /Applications/Photos.app/Contents/MacOS/Photos

Identifier: com.apple.Photos

Version: 4.0 (3441.7.100)

Build Info: PhotoApp-3441007100000000~1

Code Type: X86-64 (Native)

Parent Process: ??? [1]

Responsible: Photos [781]

User ID: 501

Date/Time: 2019-05-12 16:54:49.798 -0700

OS Version: Mac OS X 10.14.4 (18E227)

Report Version: 12

Anonymous UUID: 4C546761-E0E9-C7AB-96A3-34ABDE05E1E1

Time Awake Since Boot: 2600 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:

Assertion failure in -[IPXActivityViewAssetsSectionInfo cloudFeedAssetsEntry], /BuildRoot/Library/Caches/com.apple.xbs/Sources/PhotoApp/PhotoApp-3441.7.100/app/spark/Source/Shared/ActivityView/Model/Section Infos/IPXActivityViewAssetsSectionInfo.m:36

unexpected activity view entry class

abort() called

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

0 libsystem_kernel.dylib 0x00007fff6135a2c6 __pthread_kill + 10

1 libsystem_pthread.dylib 0x00007fff6140fbf1 pthread_kill + 284

2 libsystem_c.dylib 0x00007fff612c46a6 abort + 127

3 com.apple.PhotoFoundation 0x00007fff55f53a0b -[PFAssertionPolicyAbort notifyAssertion:] + 58

4 com.apple.PhotoFoundation 0x00007fff55f53131 -[PFAssertionPolicyComposite notifyAssertion:] + 221

5 com.apple.PhotoFoundation 0x00007fff55f5332e -[PFAssertionPolicyUnique notifyAssertion:] + 232

6 com.apple.PhotoFoundation 0x00007fff55f528ca -[PFAssertionHandler handleFailureInFunction:file:lineNumber:description:arguments:] + 164

7 com.apple.PhotoFoundation 0x00007fff55f524c3 _PFAssertFailHandler + 274

8 com.apple.Photos 0x000000010cb26ece -[IPXActivityViewAssetsSectionInfo cloudFeedAssetsEntry] + 117

9 com.apple.Photos 0x000000010cb26d93 -[IPXActivityViewAssetsSectionInfo updateFromCloudFeedEntry] + 70

10 com.apple.Photos 0x000000010cb1d129 -[IPXActivityViewSectionInfo reload] + 27

11 com.apple.Photos 0x000000010d012bf1 __91-[IPXActivityViewSectionInfosManager loadSectionInfosAtIndexes:immediatelyLoadNewSections:]_block_invoke.213 + 129

12 com.apple.CoreFoundation 0x00007fff34d58243 __NSArrayEnumerate + 529

13 com.apple.Photos 0x000000010d0122d6 -[IPXActivityViewSectionInfosManager loadSectionInfosAtIndexes:immediatelyLoadNewSections:] + 390

14 com.apple.Photos 0x000000010cad5eed -[IPXActivityViewController _updateWindowOfLoadedSectionInfos] + 306

15 com.apple.Photos 0x000000010cad5d6c -[IPXActivityViewController _updateInterfaceForModelReloadAnimated:] + 462

16 com.apple.Photos 0x000000010cb1a9a6 -[IPXActivityViewController activityViewSectionInfosManager:sectionInfosDidChange:] + 533

17 com.apple.Photos 0x000000010d013306 __58-[IPXActivityViewSectionInfosManager _rebuildSectionInfos]_block_invoke + 1268

18 com.apple.PhotoFoundation 0x00007fff55f9596d __PFMainRunLoopPerformAsync_block_invoke + 25

19 com.apple.CoreFoundation 0x00007fff34d4e4f0 __CFRUNLOOP_IS_CALLING_OUT_TO_A_BLOCK__ + 12

20 com.apple.CoreFoundation 0x00007fff34d12057 __CFRunLoopDoBlocks + 392

21 com.apple.CoreFoundation 0x00007fff34d11db6 __CFRunLoopRun + 2783

22 com.apple.CoreFoundation 0x00007fff34d11085 CFRunLoopRunSpecific + 459

23 com.apple.HIToolbox 0x00007fff33fef9db RunCurrentEventLoopInMode + 292

24 com.apple.HIToolbox 0x00007fff33fef715 ReceiveNextEventCommon + 603

25 com.apple.HIToolbox 0x00007fff33fef4a6 _BlockUntilNextEventMatchingListInModeWithFilter + 64

26 com.apple.AppKit 0x00007fff32389ffb _DPSNextEvent + 965

27 com.apple.AppKit 0x00007fff32388d93 -[NSApplication(NSEvent) _nextEventMatchingEventMask:untilDate:inMode:dequeue:] + 1361

28 com.apple.AppKit 0x00007fff32382eb0 -[NSApplication run] + 699

29 com.apple.AppKit 0x00007fff323723f0 NSApplicationMain + 777

30 libdyld.dylib 0x00007fff6121f3d5 start + 1