convert.ly error message - 64bit Mac - Catalina

[Zone Dremik]

Hello,

I just upgraded to Mac OS 10.15.5 and now convert.ly has stopped working 
entirely. I get the following error message;

arch: posix_spawnp: 
/System/Library/Frameworks/Python.framework/Versions/2.7/bin/python2.7: Bad CPU 
type in executable

No change is made to the file.

I had been using the 64bit bit version of Lilypond 2.20.0 from Marnen for some 
time, and that is still working fine otherwise.

This message appears when I try to run convert.ly from Frescobaldi. (When I run 
convert.ly from Lilypond it doesn't crash, but only changes the version number 
in the code.)

Is this a Frescobaldi issue? I couldn't find a link to a users group on the 
Frescobaldi website.

I am using Lilypond/Frescobaldi on a strictly consumer level, although I have 
been able to update obsolete syntax by referring to the online documentation. 
It would be nice to have convert.ly back again.

Thank you

Lilypond:
Version 2.20.0 (Build from 11-03-2020 16:32)


Frescobaldi: 2.20.0
Python: 3.5.3
python-ly: 0.9.5
Qt: 4.8.7
PyQt: 4.12
sip: 4.19.1
poppler: 0.51.0
python-poppler-qt: 0.24.0
OS: Darwin-19.5.0-x86_64-i386-64bit
installation kind: standalone app bundle

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interested in early music?
I recently discovered the work of Elam Rotem on the Early Music Sources 
project, and it's fantastic!
earlymusicsources.com