In most cases, problems with fonts have been caused by malformed font files giving trouble to Fontconfig. If you experience crashes at start-up when GIMP scans your font directories, as a quick workaround you can start GIMP with the --no-fonts command line argument, but then you will not be able to use the text tool.

A frequent source of confusion occurs on Windows systems, when GIMP encounters a malformed font file and generates an error message: this causes a console window to pop up so that you can see the message. Do not close that console window. It is harmless, and closing it will shut down GIMP. When this happens, it often seems to users that GIMP has crashed. It hasn't: closing the console window causes Windows to shut GIMP down. Unfortunately, this annoying situation is caused by an interaction between Windows and the libraries that GIMP links to: it cannot be fixed within GIMP. All you need to do, though, if this happens, is minimize the console window and ignore it.