Captivate 10: Effect file not valid??

Do you see a Preview in the Effects part of the Timing Properties panel when you hover over that effect with an object selected? Flicker is an effect that is supported also for HTML5 output, including responsive projects. Is this happening only in one project or can you repro in a new project? No problems with the other effects of the Emphasis category?

I checked the date of the XML file for this effect, is 6/4/2017. Can you check in the Gallery\Effects\Emphasis?

This is the XML-file, which is functional for me:

<Motion duration="30" xmlns="fl.motion.*" xmlns:geom="flash.geom.*" xmlns:filters="flash.filters.*">

<source>

<Source frameRate="30" x="155.95" y="133" scaleX="1" scaleY="1" rotation="0" elementType="movie clip" symbolName="Text caption">

<dimensions>

<geom:Rectangle left="-87.95" top="-32" width="175.95" height="64"/>

</dimensions>

<transformationPoint>

<geom:Point x="0.49985791418016484" y="0.5"/>

</transformationPoint>

</Source>

</source>

<Keyframe index="0" tweenSnap="true" tweenSync="true">

<tweens>

<SimpleEase ease="0"/>

</tweens>

</Keyframe>

<Keyframe index="14" tweenSnap="true" tweenSync="true">

<color>

<Color alphaMultiplier="0"/>

</color>

<tweens>

<SimpleEase ease="0"/>

</tweens>

</Keyframe>

<Keyframe index="29" tweenSnap="true" tweenSync="true">

<color>

<Color/>

</color>

<tweens>

<SimpleEase ease="0"/>

</tweens>

</Keyframe>

</Motion>