Updating library hangs up

Thanks for the tip, this fixed my issue with Photos being stuck at 18% after opening it for the first time after the 10.11 update.

I Have the same issue. When do you press alt command? On startup of the Mac or when you startup photos? I now have a screen "repairing library", it is stuck at 0%. Thanks

@diver1, I held down alt+command when I opened Photos. It then confirmed if I wanted to repair.

I have same problem, Photos has reached 17% Preparing Library and now stuck for several hours.

I've force quit the app, and tried numerous times to load it with Alt+CMD keys pressed, but no joy, it loads straight into the Welcome screen and the big blue button 'Get Started'.

Can anyone give me a clue on how to get to the repair option?

Cheers, Dave

UPDATE: Just found out how to do it. Continue to hold CMD+Alt keys while clicking on Get Started button. Now to see if the repair works.....

Replying to my pwn post here, in the hope it helps others who may expereince same issue.

I managed to enter Repair mode as per above, however, when it tried to repair the iPhoto Library it gave the below error (Library could not be opened) when it reached 5%. Tried several times, and even reverted to original photo library from Time Machine backup and same effect each time.

I decided to give the conversion one last try, and left it over night. By about 2 hours it was stuck at 17% again. However I decided to check the file system, and i could see that the preparation folders which Photos created where incrementing in number of files, and time stamp. So it looked like it wasn't stuck at 17% and was in fact performing the conversion of the library.

Result, This morning I find Photos is up and running with my photo library, all 285GB of it !! Phew!

The original iPhoto library file size was 304GB, and after the conversion I have the two files as shown above. I presume it is safe to delete the 'iPhoto Library.migratedphotolibrary' file ? I'll backup and see what happens when I do.

Thank you for your advice! I was already so devastated after trying everything else out! it was actually all about patience 🙂