The Multisession tab provides the option to create multisession discs for data discs. Multisession discs can be burned in multiple sessions until you have reached the maximum disc capacity. A session is a self-contained data area that is burned using a single process, and consists of a lead-in (with the table of contents), one or more tracks, and a lead-out. Discs without the multisession option, e.g. Audio CDs, are burned in a single session. 
If a new multisession disc is being started, Nero Burning ROM also saves (if possible) the point of origin for the files. This information is used when continuing the multisession disc.  
If a multisession disc is being continued, Nero Burning ROM automatically sets a cross reference to the imported session, i.e. the table of contents for the imported session is copied to the table of contents for the current session. You must define which session is being imported at the start of the burn process. The files in the previous sessions are retained and continue to take up space.
In this case Nero Burning ROM automatically verifies whether the correct multisession disc has been inserted for continuation. If not, the disc is ejected.

 

 

 

If you disable the Finalize disc check box on the Burn tab, you can always burn additional sessions on the disc, but then only the last session will be visible and you will only be able to access data from the final session.

 

 

 

 

Multisession disc
Multisession discs are particularly suitable for backing up important files burned on a regular basis.  

 

 
The following configuration options are available on the Multisession tab in the Multisession area:
Option button
Start Multisession disc

Burns the selected compilation in one session to the disc. 
If the disc already contains sessions, you can also select this option. Sessions are then not imported and cross references are not set. This means that only the last session will be visible and you will only be able to access data from the final session.

Option button
Continue Multisession disc

Continues a multisession disc by burning an additional session to a disc with at least one session. Cross references to the imported session are set in the process. 

Option button
No Multisession

Creates a disc without a multisession.
However, even a disc without a multisession can be continued as long as it is not fixated. Sessions are then not imported and cross references are not set. This means that only the last session will be visible and you will only be able to access data from the final session.

 

Multisession Settings