Photo library won't open after update, only shows buffer icon. What to do??

Hello FreiMel,

After reviewing your post, it sounds like the Photo library will not open. I would recommend that you read this article, it may be able to help the issue.

Use the Photos library repair tool - Apple Support

1. Hold down Option-Command while you open Photos.
2. In the dialog that appears, click Repair to start the repair process.

Thanks for using Apple Support Communities.
Have a nice day

Backup your Photos library and launch Photos while holding down the option and command keys and repair your database

LN