Hi

We need more information:

1. Computer specification - processor make/model, graphics card or chipset, RAM,  hard drive configuration, sizes and free space?
    
2. Windows version and is it up to date?  Press and hold down the Windows key and the R key - in the dialog that opens type in winver and press enter.
    
3. Software full name and version number - as found under Help, About . . .
    
4. A screen shot of the timeline may help.
    
5. Is the jitter in the Preview screen or when you export the slideshow?
    
6. Are the 'slides' that jitter video or still images?
    
7. If video can you analyse one of the video clips with MediaInfo and post the results along with the Export settings you are using for the slideshow.

Also please read before replying and add any other information you think may be relevant.

John EB