QuickTime Player on Big Sur no longer loads 3rd Party CoreMediaIO DAL plugin

Number:rdar://FB8798808 Date Originated:2020-10-13
Status:Open Resolved:
Product:macOS Product Version:11.0 Big Sur Beta 9
Classification:vug Reproducible:yes
QuickTime Player in macOS 11 Big Sur beta 9 refuses to load DAL plugin with following messages:

Library Validation failed: Rejecting '/Library/CoreMediaIO/Plug-Ins/DAL/PTPWebcamDALPlugin.plugin/Contents/MacOS/PTPWebcamDALPlugin' (Team ID: ZYF8X9Z6M2, platform: no) for process 'QuickTime Player(2097)' (Team ID: none, platform: yes), reason: mapping process is a platform binary, but mapped file is not

Error loading /Library/CoreMediaIO/Plug-Ins/DAL/PTPWebcamDALPlugin.plugin/Contents/MacOS/PTPWebcamDALPlugin:  dlopen(/Library/CoreMediaIO/Plug-Ins/DAL/PTPWebcamDALPlugin.plugin/Contents/MacOS/PTPWebcamDALPlugin, 0x0106): code signature in (/Library/CoreMediaIO/Plug-Ins/DAL/PTPWebcamDALPlugin.plugin/Contents/MacOS/PTPWebcamDALPlugin) not valid for use in process: mapping process is a platform binary, but mapped file is not

This seems to indicate that QuickTime Player is in the SIP/platform domain, and thus does no longer allow 3rd party video sources. I'd consider this a bug, as this severely limits a user's ability to record with the app, for no apparent reason. On [revious versions of OS X, 10.15 and before, QuickTime Player was sandboxed but not restricted in such a way.


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