Werner's suggestion led me to compare the convert-ly scripts in a
copy of 2.10.13 and 2.10.15.
The path for MacOS is LilyPond.app -> Contents -> Resources -> bin -
> convert-ly .
The following lines were missing in 2.10.15:
datadir = '/usr/share/lilypond/2.10.13'
if not os.path.isdir (datadir):
datadir = '/usr/share/lilypond/2.10.13'
sys.path.insert (0, os.path.join (datadir, 'python'))
# dynamic relocation, for GUB binaries.
bindir = os.path.abspath (os.path.split (sys.argv[0])[0])
for p in ['share', 'lib']:
datadir = os.path.abspath (bindir + '/../%s/lilypond/current/
python/' % p)
sys.path.insert (0, datadir)
I copied, then pasted them into the 2.10.15 convert-ly script, then
changed the occurrences of "2.10.13" to "2.10.15" in the copied
text. All is well until 2.10/11. 16 comes outl