Document Really Ugly Bugs (coredumps, assert fails, etc) [Linux Intel] LilyPond occasionally crashes while parsing the initialisation files. This is a very obscure bug, and usually entering the commandline differently "fixes" it. lilypond input.ly and lilypond -I. ./input.ly makes a difference Typical stacktrace: SIGSEGV __libc_malloc (bytes=16384) ?? () yyFlexLexer::yy_create_buffer () Includable_lexer::new_input (this=0x8209a00, s={strh_ = { : I get bitten by this every once in a while, and I am very interested in hints what might be wrong. This problem has only been identified with libc-5.3 and libc-5.4 platforms, so you might try upgrading to 6.0, ie. GNU libc-2.