Sometimes ghost images or sounds can appear in your project even though there are no objects at that position in the project.
To fix this problem, follow these steps:

1. Switch to Timeline mode and zoom out of the project until you are able to draw a selection box around the entire movie and all of its tracks. 
2. Select the entire project and go to "Edit" > "Copy objects" (keyboard shortcut: Ctrl+C) to copy it. Depending on the size of your project, it may take some time to copy everything to the clipboard.
3. Now, without closing the current project, open a new project by going to "File" > "Manage movies" > "New".
4. Users of MAGIX Video Pro x can open a new project via "File > Manage project > Add new empty movie".
5. Go to "Edit" > "Paste objects" (or press Ctrl+V).
6. Then, select the tab for the "old" movie (above the timeline) and remove it from the project by clicking the small "x" icon.