Just wanted to share this knowledge since it took 3 days of troubleshooting to isolate the problem, perhaps it is a bug with Captivate 2019. I use everything in my modules, including video, advanced actions, quizzes etc. Recently changed to TalentLMS and preivously produced modules would not load properly using the TalentLMS app on smartphones. TalentLMS people didn't have a clue, even though I sent them the scorm to examine. They said it looked like the scorm was authored to play only in a browser and that they were working on some bug in their app. I thought it was my new phone causing the problem. Upon playing the module, only a white screen would appear, then a gray screen with progress blocks spinning with "loading" message. Then it went to the first slide, by passing my preload button/start screen. Audio played but the slide was blank, except for the "begin" button, missing it's text, that I use on my intro slides. I thought it was a master slide background problem on slide #1 because the "begin" button was clickable, worked going to slide #2 and the rest of the module played fine. It turned out after 21 different zip uploads to be nothing more than the slide quality setting on slide #1 was set to "optimized." All others were set to "24bit high quality." Simply changing that slide to 24bit quality, to match the others worked. In fact just the yesterday I uploaded another that went through the same launch problems. Turns out that the quiz question slides I added were set to "optimized." Changed them to "24bit quality" and it works fine. This might be common knowledge, but with the depth of this app it could have been any combination of user error when publishing the scorm. It seems that having "retain slide quality settings" somehow does not like the fact that there was an optimized slide mixed in with the "24bit quality" slides. On a different note, I strongly suggest that anyone using Captivate 2019 go and take the Captivate Specialist Program. Most helpful thing you can do to understand the app and use it to it's fullest potential. Even with the unfriendly GUI, Captivate is The Killer App. It has a steep learning curve because it offers infinite user control of what it does. You just need a good working memory to realize it's full potential.