[Nate Winspear] “Sony’s Content Browser”
Try Catalyst Browser, Content Browser is dead.
https://www.sonycreativesoftware.com/catalystbrowse
Catalyst Browse system requirements
A 64-bit operating system: Microsoft® Windows 7, Windows 8.1, or Windows 10 or macOS 10.11 (El Capitan), 10.12 (Sierra), or 10.13 (High Sierra)
2 GHz processor (multicore or multiprocessor CPU recommended for HD; 8 cores recommended for 4K)
500 MB hard-disk space for program installation
Solid-state disk (SSD) or high-speed RAID for 4K media
4 GB RAM (8 GB recommended; 16 GB recommended for 4K)
NVIDIA, AMD/ATI, or Intel GPU with support for OpenCL 1.1 or later with at least 512 MB of memory (2 GB recommended for 4K) or a CPU with SSE 4.2 or higher. OpenGL 2.1 is recommended for optimum performance.
And if you’re on OS 10.12.6 you probably don’t have the current version of FCPX either. as it requires 10.13.2 and later.
Using software that predates Sony’s update means that the older programs you have may not have been updated to handle the codec.