Separate a managed sync copy from an independent archive
A second copy on an external drive may look reassuring, but first establish how it was created and which application manages its lifecycle. Emby’s Downloads and Sync introduction identifies the source files and libraries as the master: removing them also removes their downloads. That relationship matters before reorganising a source library or treating a sync destination as the only remaining archive.
Check the Folder Sync setup and user access
Folder Sync is an Emby Premiere administration feature provided by a plugin. Its documented setup includes installation, a server restart, and creation of a destination with a path and display name. Administrators can grant access to all users or select particular accounts. The named destination then appears in Download to for users allowed to create jobs there. A destination missing for one account therefore calls for a permissions check as well as a check that the folder was configured.
Use destination names that explain their purpose
For example, a home-video server might prepare lower-bitrate copies in a clearly named mobile destination while keeping the original production files elsewhere. Check the destination selected in the job, the requested quality and the resulting alternate version. Do not remove the source simply because conversion has completed. Before a larger storage change, establish which copies are independently retained and which remain governed by the server’s sync job. This makes a missing destination, a missing alternate version and a source-removal consequence three observable stages rather than one vague report that the external drive lost a film.
Questions, answered
Can I remove the master library and assume its synced downloads remain?
No. Emby documents that downloads are removed when their source files or libraries are removed.