2.31 Online and Offline Media Items
By default, REAPER sets all media items offline when the program loses focus.
Kind: concept (user-guide-section) Chapter: 2 REAPER Project Basics Source: REAPER User Guide v7.70
By default, REAPER sets all media items offline when the program loses focus. To change this disable the option (Options. Preferences, Media) to Set media items offline when program is not active. You can also use the Item, Media command from REAPER’s main menu to set all or selected media items on or off line.
If any media items are still flagged as offline even when REAPER is active, or when a project is loaded, this is likely to mean either that the media files are to be found in a directory and/or drive other than the project directory, or that it has been deleted altogether. Note that REAPER’s editing is will never delete files.