For a couple of weeks, instead of seeing thumbnails in my Nautilus folders, I just see the default “Still Loading” icon. This is very annoying to me. Searching around people just suggest deleting the folder where thumbnails are cached.

If you need to debug Nautilus, like if it continues to have trouble creating thumbnails, look into the debug log options on this page. This didn’t help me very much- the thumbnailers don’t seem to output but you may find something useful with that log file.

If that’s happening to you, do these things:

  1. First try the simple solution- F5 which tells Nautilus to refresh. Sometimes it just hasn’t displayed the thumbnail it has ready for you. If that doesn’t work, continue to step 2.
  2. In a terminal, run rm -rf ~/.thumbnails
  3. Now run killall nautilus

When Nautilus restarts, it will begin creating thumbnails right away.

What I noticed is that when I opened a folder with lots of files, the thumbnailing would proceed quickly whenever you do the last two steps in my list above (clearing the thumbnail cache and restarting nautilus). A visual way of debugging is to then look for the first file that is trying to create a thumbnail and is not succeeding. For me it’s stopping on creating a thumbnail for an html file. gconf, the GNOME Configuration Editor, tells me when I search (Edit > Find) for ‘html’ that those thumbnails are handled by gnome-web-photo from the openSUSE-11.1-OSS repository. You can, in gconf, just disable that thumbnailer and restart Nautilus again.

But I want html thumbnails! Must have them! So I get the command that is being run from gconf and run it directly in the terminal like this:

gnome-web-photo --mode=thumbnail --size=256 records.html ~/Desktop/records.png

with this result:

(gnome-web-photo:16037): GLib-GObject-WARNING **: cannot register existing type `GtkMozEmbed'

** (gnome-web-photo:16037): CRITICAL **: void gtk_moz_embed_realize(GtkWidget*): assertion `GTK_IS_MOZ_EMBED(widget)’ failed

I’ll figure it out eventually. I’m betting it’s because I’m using Firefox 3.5 from the mozilla repository on the openSUSE Build Service and I see that I have three separate versions of xulrunner installer. I don’t know for sure but I believe xulrunner provides the files this is choking on. Again, I could be wrong.

Keep in mind that you may also be hitting a ceiling on how much space your thumbnails are taking up. People have tons of files, photos, documents, movies and once these each have a thumbnail, it’s possible to overwhelm the 512 MB that GNOME sets aside for use by the thumbnailers. It may be enough, but if you have a big hard drive, you can up the limit like this:

  1. Open gconf and search for ‘thumbnail’
  2. In the search results select ‘/desktop/gnome/thumbnail_cache’
  3. In that node there are two options, maximum_age and maximum_size. maximum_size’s tip says “Maximum size of the thumbnail cache, in megabytes. Set to -1 to disable cleaning.” and maximum_age’s says “Maximum age for thumbnails in the cache, in days. Set to -1 to disable cleaning.”. I set them both to -1 but I’m guessing I will change maximum_age to something else since otherwise I will likely have stale thumbnails which is still a bit annoying.
  4. In a terminal, run rm -rf ~/.thumbnails
  5. Now run killall nautilus