The Discogs and MusicBrainz wizards have a Release Details display which has a table at the top which contains the set of items which can potentially be imported. This topic discusses how the import settings get set when the panel is first displayed.
Both wizards retain the state of the settings when the wizard was closed. Assuming nothing else has been done, the next time the wizard opens, each item will be set to the previous state.
If the Import Settings item is set and an import is performed, each track will have a UDTI written named Discogs Import Settings or MusicBrainz Import Settings. When a wizard is started, if there is a consistent Release ID and a consistent Discogs Import Settings or MusicBrainz Import Settings value, the retained import settings will establish the initial state of the settings displayed in the Release Details panel.
Each time you import metadata from a wizard the Discogs Import Settings or MusicBrainz Import Settings value will be rewritten, if Import Settings is enabled. This will potentially change what import settings will be enabled the next time the release is displayed in the wizard. If you want to completely remove any modification to the display when a release is loaded, simply delete the Discogs Import Settings or MusicBrainz Import Settings UDTI and uncheck Import Settings.
Both wizards have the ability to retain a settings layout. The Import Settings Manager is displayed via the wizard's Release Details view's context menu. They can also be accessed from the Access Discogs and Access MusicBrainz statements' custom table's context menu. You can create, delete or load an import settings set.
Note that is also possible to set per track exclusions from the actions menu. Any track which has an exclusion set will simply not import any excluded metadata items, regardless as to how they are set in the Release Details table. To stop excluding items delete the appropriate Discogs Exception Mask or MusicBrainz Exception Mask UDTI.