Try this to see if it does what youn want
In preferences/editing- uncheck Collapse root when no Time selection is present
Then move cursor to a any position on TL
John,
the "collapse loop region when no time selection is present" option appears to have been removed for Movie Studio Platinum 12.0 due to a decision made by the developers. If you'd like to see it again, or if you have other suggestions for our applications, please visit the product suggestion page.
The italics text is from the SCS Support answer to my query on this.
Make it a habit of making the loop region zero. With the cursor anywhere on the timeline press the "i" and "o" keys (In and Out) That will put the start and end of the loop region at the same point on the timeline.
AND ... make it a habit of checking to see if the "Render loop region" box is checked before each render.
Either one will work but get in the habit of doing both for backup.