cynarion
Level 1 (0 points)

Q: How do I regenerate Photos thumbnails after hard drive restore?

Hi!

 

A couple of weeks ago, our iMac hard drive failed and was repaired under the hard drive replacement program. I restored our system from our latest backup, but all our photo thumbnails in Photos are either black or white with no detail. When we open an individual photo, it's there, but the thumbnails aren't visible, making browsing impossible.

 

I've tried repairing the library. That didn't do anything.

 

I've tried rotating the photos. Rotating the last import (300 photos) back and forth regenerated the thumbnails okay, but it also took 6.5 minutes. I have 80,000 photos. By my estimate that makes for a little over 12 days (assuming a linear extrapolation, anyway), during which time my CPU will be under a lot of stress.

 

I have also noticed that the rotation trick does nothing for videos.

 

So I figured, as a last resort before I put my Mac into two weeks of enforced no-touching, I'd ask if anyone had any other ideas.

 

Also, does anyone know how to regenerate thumbnails for videos?

 

Thanks in advance!

 

--Mike

iMac (27-inch, Late 2012), OS X Yosemite (10.10.5)

Posted on Jan 29, 2016 4:10 PM

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cynarion

Q: How do I regenerate Photos thumbnails after hard drive restore?

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  • Helpful answers

  • by Old Toad,

    Old Toad Old Toad Jan 29, 2016 4:37 PM in response to cynarion
    Level 10 (141,105 points)
    Mac OS X
    Jan 29, 2016 4:37 PM in response to cynarion

    First try rotating a batch of thumbnails 90º one direction and the  90º back.  See if that will restore them.  If it works then do batches at a time, not the entire library.

     

    If that fails try repairing the library according to the instructions in this Apple document: Repair Your Library.

    Warning: If you use iCloud Photo Library with Photos, this action will cause Photos to upload all your pictures again (from Fix missing or incorrect thumbnails in Photos - Apple Support).

    OTsig.png


  • by cynarion,

    cynarion cynarion Jan 29, 2016 4:44 PM in response to Old Toad
    Level 1 (0 points)
    Jan 29, 2016 4:44 PM in response to Old Toad

    I have tried both of those things. I am asking if anyone has any other ideas or options.

     

    Also. I'm interested in whether there is anything in particular I can do to regenerate video thumbnails, since they don't seem to be fixed by either of the above actions.

  • by Old Toad,

    Old Toad Old Toad Jan 30, 2016 10:00 AM in response to cynarion
    Level 10 (141,105 points)
    Mac OS X
    Jan 30, 2016 10:00 AM in response to cynarion

    Try doing a minor edit on one of the problem photos.  Does that create a visible thumbnail?  If it does when happens when you do a revert to original on it?

  • by compfusion,

    compfusion compfusion Apr 21, 2016 12:25 PM in response to cynarion
    Level 1 (12 points)
    Apr 21, 2016 12:25 PM in response to cynarion

    Hi,

    I had the same question ... my iPhotos library gave black thumbnails in Photos. I also tried the rebuild library method. It did not work.  Rotating/re-rotating photo thumbnails does work for photos but would take forever.  This method does not work for videos at all.  However, I just discovered if you duplicate the video (or photo), the newly created thumbnail has the picture in it and isn't black. Of course this would take a lot of time (and require deleting of original subsequently), but it's better than nothing - seems quicker than rotate/re-rotate and does work for video thumbnails.

  • by Old Toad,

    Old Toad Old Toad Apr 21, 2016 2:12 PM in response to Old Toad
    Level 10 (141,105 points)
    Mac OS X
    Apr 21, 2016 2:12 PM in response to Old Toad

    Here's another method to regenerate all of the thumbnails in a Photos library that was developed by user YongrokKim:

    YongrokKim

    Apr 18, 2015 7:45 PM

    Re: thumbnails not as the picture is!

    in response to YongrokKim

    Helpful

    In my case, after deleting thumbnail data file from Photos library, it started working well again.

     

    It makes Photos regenerate thumbnails and looks good to me.

     

    Those thumbnail files are located in " [photos library path] / Thumbnails / Segments / "


    Highlight001.jpg

     

    OTsig.png

  • by ThorstenMeyer,

    ThorstenMeyer ThorstenMeyer May 19, 2016 1:19 AM in response to Old Toad
    Level 1 (4 points)
    May 19, 2016 1:19 AM in response to Old Toad

    I'm currently trying this with my backup-Library and it seems to work!

    The files inside the Segment-Folder are constantly changing and the Thumbs are recreated.

    It will need some time for around 45.000 Images, but i think this will do the trick!

    Thanks a lot!