AMD CPUs are qualified by Avid on lenovo and Boxx workstations, there should be no architectural issues at play here.

when you say removing the audio helps the issue, are you disabling tracks or removing them from sequences?
do you normally work with waveforms enabled? what about Fast scrub?

media composer 7 is ancient. If you want to upgrade to a recent version of macos, you are technically hosed.

Please refer to the media composer version matrix for further details:
https://avid.secure.force.com/pkb/articles/en_US/Compatibility/en267087

You can’t have two different hardware IO devices attached and active in composer, but you can use multiple outputs from the same hardwareIO device, including hardware down/crossconvert where applicable.

this isn’t a supported workflow for media composer. Network shares can be used for source media and linked media, but not native media…officially.

There is a console command “alldrives” that will enable the usage of some unsupported storage types for native media. open the console with CMD+6, enter “alldrives” without the quotes, and hit enter.…

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yes, it is possible to export a Linked sequence directly. The error you are seeing is related to the audio contents of your sequence, or perhaps to the destination audio format you have chosen in export settings. Can you share a screenshot of the export settings you are using?

you might also try to export to MXF op1a and use a third party app to…

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Trevor, is there a reason you don’t want to upgrade? mostly just curious.

QT ref and QT Same-As-Source are not available in MacOS 10.15 with media composer. You can install the legacy quicktime components for some Quicktime functions. Recomended workflow is to kick out a DNX OP1a MXF file and encode externally for H.264 or other highly compressed formats.