Changing movie clip to graphic causes white screen?

Using two instances of the same symbol in a project. When I test the project after placing the first instance on the stage as a movie clip, project works fine. When I place the second instance on the stage as a movie clip, project works fine. When I convert movie clip to symbol, the screen comes up white when I test project. When I break the symbol into components, screen still appears white. Even erasing the graphic instance or the componentes still causes the screen to come up white. Only solution I've found is using undo.

Has anyone else experienced this?  Converting to movie clip to symbol  "whiting out" your project? I'm refraining from adding sample code just yet, because code is pretty bulky and not sure what or if it would be relevant. Wondering if there's s known cause of something like this that doesn't require me to post code