Sometimes reinstalling the application is necessary when you experience a technical issue such as a crash at the start. 

- In the Finder, choose Go > Go to Folder.

- In the Go To Folder dialog, type ~/Library
Click Go.

- Open Preferences folder.

Once you have open that folder, look for ' com.movavi ' files and remove all the files that have that in the name.

We recommend searching those files manually.  

- remove the program to Trash and clean the Trash;

- redownload the program by using the Lost key form, or using your Appstore account if your program was obtained through Appstore;

- install the program once again.