I had a running environment under Mac OS Sierra. I switched to high Sierra (beta) and now nrftuil cannot import a file that looks like it is there to me!
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> > nrfutil pkg generate --hw-version 52
> > + --debug-mode
> > + --key-file //keys/ruuvi_open_private.pem
> > + --application ruuvitag_b3/s132/armgcc/_build/weather_station.hex
> > + $zipname.zip
> >
> > Traceback (most recent call last):
> > File /usr/local/bin/nrfutil, line 7, in from nordicsemi.main import cli
> > File /Library/Python/2.7/site-packages/nordicsemi/main.py, line 48, in
from nordicsemi.dfu.bl_dfu_sett import BLDFUSettings
> > File/Library/Python/2.7/site-packages/nordicsemi/dfu/bl_dfu_sett.py, line 55, in
from nordicsemi.dfu.package import Package
> > File /Library/Python/2.7/site-packages/nordicsemi/dfu/package.py, line 54, in
from nordicsemi.dfu.init_packet_pb import *
> > File/Library/Python/2.7/site-packages/nordicsemi/dfu/init_packet_pb.py, line 38, in
> > import dfu_cc_pb2 as pb
> > File /Library/Python/2.7/site-packages/nordicsemi/dfu/dfu_cc_pb2.py, line 42, in
from google.protobuf.internal import enum_type_wrapper
> > ImportError: No module named google.protobuf.internal
>
40 import sys
41 _b=sys.version_info[0]<3 and (lambda x:x) or (lambda x:x.encode(latin1))
42 from> google.protobuf.internal import enum_type_wrapper
43 from google.protobuf import descriptor as _descriptor
44 from google.protobuf import message as _message
45 from google.protobuf import reflection as _reflection
> +++++++++++++++++++++++++++++++++++++
