The cause of the failure is
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Setting up mythtv-backend (0.21.0+fixes17120-0ubuntu0+mythbuntu2) ...
udev active, devices will be created in /dev/.static/dev/
chown: changing ownership of `/var/lib/mythtv/recordings': Operation not permitted
dpkg: error processing mythtv-backend (--configure):
subprocess post-installation script returned error exit status 1
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Thanks for your report.
The cause of the failure is fixes17120- 0ubuntu0+ mythbuntu2) ... mythtv/ recordings' : Operation not permitted
=====
Setting up mythtv-backend (0.21.0+
udev active, devices will be created in /dev/.static/dev/
chown: changing ownership of `/var/lib/
dpkg: error processing mythtv-backend (--configure):
subprocess post-installation script returned error exit status 1
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Affecting to mythtv