I am experiencing an issue also reported here: https://moodle.org/mod/forum/discuss.php?d=223331
Basically we just converted from 1.9.19+ to 2.4. In dev, my new theme worked great but we experienced issues once reaching the production environment.
In the conversion I changed our theme name from WaveLength to wavelength (to conform to best practices) and because I knew we had used some non-licensed images in the old theme.
Now when someone encounters one of the missing images from the now missing theme, the front page (which displays a list of the course categories) "breaks."
Instead of a list of categories and a two-column layout, it turns into one big ugly column showing all course details, descriptions, a picture of the course, and all the menus are on the very bottom of the page.
My temporary work-around is listed in the prior posting but is two-fold. I can go to the front page setting, delete the list of courses, save it, then add the list of courses back and the front page is fixed. The 2nd work-around is that I have had to create "fake" icons but the same name as the missing ones and I put them where the courses were looking for them.
HOWEVER, I may not have seen the last of the missing images.
How do I find all these bad images? Any ideas?
I would be surprised if no one has experienced this before.
FYI - I'm an IT person and do not create course content.
Thanks!
Constance