One weird error that is currently occurring for UK users - iPlayer is creating "tbn" files in the Thumbnail cache that are actually HTML files...
I'm seeing this with latest OpenELEC on Pi, using the latest iPlayer (2.6.10).
It looks as though iPlayer (or maybe Kodi) is trying download and caching an image file (the channel logo), getting an error page and then writing the contents of the error page as the image file. I've gone back to a 1 December OpenELEC build and the same error happens, so it's probably in Helix (if it's a Kodi bug) or it's simply an iPlayer issue (Wrong channel logo url? Error detection not working?)
To reproduce: Enable Kodi debugging, then go into "TV", "Watch Live", switch to Thumbnail view, click on "BBC One" (or "BBC Two"), watch a few seconds of video then click on stop.
If you have the problem, the logo of the channel you clicked on will have disappeared (it sometimes appears, in which case try again with another channel).
When the problem occurs you should see the following messages in your log relating to the caching of the channel logo:
Code:
20:24:09 129.220856 T:2722169920 INFO: plugin.video.iplayer: Reusing existing thumbfile=/storage/.kodi/userdata/Thumbnails/9/9fba1969.tbn for url plugin://plugin.video.iplayer/?pid=bbc_two&feed_channel=bbc_two
...
20:24:15 135.511841 T:2740184128 ERROR: COMXImageFile::ReadFile /storage/.kodi/userdata/Thumbnails/9/9fba1969.tbn GetCodingType=0x7fffffff
20:24:15 135.511993 T:2740184128 NOTICE: LoadJpeg: unable to load /storage/.kodi/userdata/Thumbnails/9/9fba1969.tbn
20:24:15 135.770889 T:2740184128 DEBUG: LoadFromFileInternal - Load of /storage/.kodi/userdata/Thumbnails/9/9fba1969.tbn failed.
If you try to open the cached image, in this case Thumbnails/9/9fba1969.tbn, in an image viewer, you'll discover that the file is garbage.
Instead, you can open it in a text editor, and you'll see that it contains pure text, HTML in fact.
The contents of BBC Two "tbn" is here:
pastebin