I'm new to Kicad, so as I was just playing around, attempting to add a logo to a board. I got it to work, but was a bit bumpy. Then I watched the Getting to Blinky 4.0 tutorials and tried creating a new library and adding my custom logo footprint in there. All fine, seemed to work, but as I tried to add it to my board, I too came across this error message (except in my case Pcbnew was telling me it couldn't find Labels,pretty, Divers.pretty and Discret.pretty).
So I did a search on here, found this topic. I do not understand Github, so I have no idea why yesterday I could add footprints just fine, but today, it came up with these errors.
For anyone experiencing the same, here's my solution:
I tried the Library Wizard thing, and it seemed it was doing its thing, but it still wouldn't let me add a footprint (same errors again). So I opened the Library Manager again, removed every single library completely, and then tried adding the Github libraries using the Wizard, and finally, that worked.
I suppose I could've just deleted the 3 broken ones, but for the sake of keeping things in sync, I decided I needed to completely rebuild the library table.
Seems a bit too much of a hassle every time someone messes with the Github libraries. I understand if Kicad gives me a warning message (These libraries could not be found and are therefore disabled; Click here to delete the offending libraries from fp-lib-table (for example)), but then it should still let me choose any other footprint. Would be nice if it didn't completely gave up (just a suggestion).