This sounds like a total nightmare but I found some hints that could
lead to a solution. We can simplify the definition of a syndrome as
a set of symptoms that seems to be related by a common cause. My DK
is experiencing several symptoms that seems to have a common cause
despite their differences.
First the main symptoms of this "crazy thumbnail syndrome":
- when grouping by Album, there are some album/folders that do not
show all their content. As an example it shows two thumbnails
despite the counter states 10 and using dolphin I confirmed there
are indeed 10 photos there. Some of my albums appear completely
empty. So, the hidden thumbnails is the first symptom.
- large empty spaces between the albums. This may be just a
consequence of the previous symptom because albums that showup with
all their thumbnails, have no empty spaces separating from next
- the most weird, is that passing the pointer over some thumbnails,
they change!!! I mean the thumbnail changes and even the text
underneath too corresponding to other photo. It switches from the
thumbnail corresponding to the file A to the file B just by passing
the mouse on top rendering the thumbnail itself unreliable since I
do not really know if it corresponds or not to that album. Funny,
when I scroll up or down a bit, these switched thumbnails return to
the previously shown thumbnail. Again, mouse-over makes the
thumbnail to switch again repeating consistently the behavior.
- the switching thumbnails can occur as a complete change among
thumbnails or a partial case as overlapped thumbnails depending on
the zoom setting of the Thumbnail view mode.
- when filtering it is the same nightmare showing lesser thumbnails
that the real content of the folders.
- this is only happening to some images and not all images, they are
always the same with problematic thumbnails and despite their
thumbnails show-up perfectly fine when selecting their album
directly (not as sub-tree).
Too complex or needing a visual? ok, look this unlisted video and
focus on the content of albums 04 and 02...
Now some light over this syndrome...
* I checked the database connecting externally to it, and it is
perfect. Data allocated inside is fine, with all the tags perfect
etc. Great. So it is just the way DK presents on screen the
* erasing thumbnail.db to force rebuild the thumbnails or using the
rebuild tool does not solve the problem.
* Using Table instead of Thumbnail view mode, the thumbnails are all
shown and there is no crazy mouse-over nor large black empty spaces.
However the "group images by album" does not do anything on Table
view (that is another issue anyway). The point is that the problem
occur only under Thumbnail view mode and that all these symptoms
have a common cause because all of them are solved by simply
changing the view mode.
* I tested every visualization combination and all the previous
symptoms occur under a specific visualization setting and only to
some images (not all). I did not find anything special (yet) to the
images whose thumbnails are shown under some settings and those that
are shown properly despite the settings.
The combination of terror is when having menu/View/ all the next
a) Thumbnail view mode
b) enable the "include album sub-tree" and "include tag sub-tree"
c) Sort Images set on "by Date"
d) Group Images set on "by Album"
Any other combination is fine, but sadly this is the most useful for
just by changing "Sort Images" from "by Date" to "by Name" solves
the problem, no more crazy mouse-over behavior changing thumbnails,
nor missing thumbnails nor empty spaces. Since the file names from
my camera are time correlative, it ends by presenting the Thumbnails
in an almost same way to "by Date". Also, by changing "Group Images"
from "by Album" to "Flat list" solves the symptoms.
These findings suggest that our files are fine, since DK is able to
show their thumbnails properly in most cases but something is weird
when combining the "Group Images by Album" with "Sort Images by
Date" visualization settings.
Probable related issues:
Some time ago, Audun posted a similar symptom (no thumbnails). Also
this link to a post that seems to have similarities as well:http://digikam.1695700.n4.nabble.com/no-photos-or-thumbnails-tp3073787.html
They do not mention the swuitching thumbnail mouse-over behavior but
as I mentioned it before, it happens also to some and not all
I cannot confirm my case is in fact related to audun's or others,
but maybe these cases can check if changing "sort images" from "by
date" to another option, solves their issues of "hidden thumbnails".
This is happening to most of our boxes:
BOX1: asus desktop / nvidia / 6 cores / opensuse 13.2 / DK 4.6.0 /
KDE 4.14.3 / Linux (x86_64) release 3.16.7-7-desktop.
BOX2: asus 4 cores / all the rest the same except it has DK 4.5.0.
BOX3: notebook HP pavillion / ATI / also with opensuse 13.2
(x86_64)/ DK 4.5.0
BOX4: notebook HP mini / ATI / also with opensuse 13.2 / DK 4.6.0 /
KDE 4.14.3 / Linux (x86_64) release 3.16.6-2-default.
BOX5: asus 4 cores quite old / opensuse 13.2 / DK 4.6.0 / KDE 4.14.3
/ Linux (x86_64) release 3.16.7-7-desktop.
So the syndrome happens on DK4.5.0 and DK4.6.0 but not always. BOX3
does not have this visualization issue (tested with the same
images). All my other boxes have the problem despite they have just
being clean-reinstalled and have different hardware. I know BOX3 had
a patch recently and BOX2 did not. Both are at the field right now
and it is hard for me to perform tests on them. However, in the case
a patch solved the problem on BOX3 (which I cannot confirm and do
not know if the problem was ever there before the patch neither),
why boxes with 4.6.0 (a more recent version) have the issue anyway?
Hope this helps to solve the issue.