In this case it would be a good idea to do a backup of your Points Of Interest, Routes and Favorites so you would not have to create them again. This simple guide could save quite a lot of your precious time.
Favorites are stored in folder /Sygic/Res/db
Routes are saved in /Sygic/Res/Itinerary
(one .itf file is one route).
Custom POIs are stored in /Sygic/Maps/Rupi/<countries>
. Points of Interest are stored for each country separately
You need to make a backup of all these folders, otherwise they will be lost.
Custom icons for Points of Interest are stored of in /Sygic/res/icons/rupi
Please make a backup of these folders. After a complete re-installation of the navigation, you need to copy them back to the same place