Hi Patrick, I'm happy to report that upgrading the package named
libarmadillo8 from version 1:8.200.0+dfsg-3 to 1:8.300.1+dfsg-1 seems to have fixed it. Why? I suspect because melt uses /usr/lib/frei0r-1/facedetect.so, /usr/lib/frei0r-1/facedetect.so interacts somehow with libopencv, (they're in the attached stack trace and valgrind log) libopencv-imgcodecs3.2 (3.2.0+dfsg-4+b2) depends on libgdal20 (>= 2.0.1) and libgdal20 (2.2.3+dfsg-1) SAYS it depends on ANY version of libarmadillo8, but it ACTUALLY needs 1:8.300.1+dfsg-1. It seems to me that the dependencies of the libgdal20 package might be updated to say it depends on at least version 1:8.300.1+dfsg-1 of libarmadillo8. Humble suggestion: If you agree, maybe you could reassign this bug report to the libgdal20 package. Happy new year, Kingsley -- Time is the fire in which we all burn.