It's important to quit or kill nautilus after the deleting the thumbnails:
nautilus -q
killall nautilus
Check failed thumbnail creation
The path for failed thumbnails (ubuntu 14.04 LTS or later) is ~/.cache/thumbnails/fail
. So just check the folder and delete them:
rm -r ~/.cache/thumbnails/fail
Force thumbnail recreation
Try changing its modification timestamp, e.g. via:
touch -m YourFile.pdf
See
How to regenerate a specific thumbnail in Nautilus?
Thumbnail recreation mechanism
According to the freedesktop documentation Thumbnail Managing Standard . You can force nautilus to recreate the thumbnail if the mtime (modification time) in the thumbnail is lower than the mtime in the original file.
Thumbnail size restriction
If an thumbnail image is larger than 10 MB, no preview will be displayed, but only the default file icon.
To fix this behaviour you can increase this limit (doubling for example):
dconf write /org/gnome/nautilus/preferences/thumbnail-limit
Thumbnailer
You can try to create a thumbnail manually to see if a PDF can be properly converted to a thumbnail (first page [0]
only):
convert -thumbnail x300 YourFile.pdf[0] thumbnail.png
~/.cache/thumbnails
(spelled differently) recursively ? Have the 3 sample thumbnails all been shown before?rm -rf ~/.cache/thumbnails/
. Every time I get the same thumbnails - somehow the first pdf always gets the 'custom icon' whereas the other 2 get the default pdf icon.