Hold saves the scene and its settings to a buffer. Fetch restores the buffer stored by the previous Hold command. The information stored includes geometry, lights, cameras, the viewport configuration, and selection sets.
Use Hold before you perform an operation that might not work as expected, that is new or unfamiliar to you, or that cannot be undone. If the results aren't as expected, you can use Fetch to return to the point where you chose Hold.
Tip: You should also use Save or Save As before you perform an operation that can not be undone; for example, applying the Collapse utility or the Reset Transform utility.
If you experience an unexpected end of operation or crash after you perform Hold, you can retrieve your scene from the buffer with the Fetch command after you restart 3ds Max.
The Hold buffer is a temporary file (maxhold.mx) in the directory specified by the AutoBackup path in the Configure User Paths dialog > File I/O panel.
Fetch also deletes all operations recorded in the Undo and Redo History lists.