This article is specific to the InqScribe 2.5 for macOS. If you're not running this version of InqScribe, please disregard.
TL;DR: To create a subtitled movie, refer to the article "How do I burn or hardcode subtitles onto a video?"
As of the v2.5, InqScribe is moving away from QuickTime as its media engine in favor of the more modern AVFoundation. After all, Apple jumped to AVFoundation back in 2011 with OSX 10.7, and completely ceased Windows QuickTime support in 2016. AVFoundation supports a wider variety of media formats with generally smother performance.
While this change offers a host of benefits, the QuickTime-specific feature "Save Subtitled QuickTime Movies" is no longer available. In its place, you can make use of the several other methods to creating subtitled movies, explained in the article "What are the different ways to create a subtitled video?".
If you rely on the QuickTime subtitling feature and are on a version of macOS prior to 10.15, you can download our previous release version 2.2.5. Please note that v2.2.5 is a 32-bit app, so it will require you to run macOS 10.14 (Mojave) or earlier. If you're using 2.2, you may find this article useful: "Advice and tips for creating subtitled QuickTime movies".