When purchasing a GeoStru software, you are provided with 2 licenses to activate the programs on two different workstations simultaneously. If you uninstall a software from a PC without deactivating it first, the license used for that machine might be lost, so it is recommended to deactivate the software first.
If you happen to lose the license due to an uninstallation without deactivation, try reinstalling the software. It should recover the license stored on the PC and then deactivate it.