To export your missing products, follow the below steps :
Step 1 : On the 'Dashboard', go to "Products >> Transfer Products", as shown in the picture below :
Step 2 : In the "Transfer Product" screen, click on the highlighted button shown in the picture below :
Step 3 : Now it will ask you to save the the file. Select the desired location and click on "Save", as shown in the picture below :
Step 4 : After saving the file, Unify Desktop will show you a message, as shown in the picture below :
You can follow the same steps to export the missing products of online store.