The application identifies previous versions of the application and will manage the database files which are stored on your machine (previous Solar Load Calculations, Custom Groups and Codes, and Log files etc). Once installed, will rename older folders and save this data.
If an error message appears, try clearing the cache files in the FenestraPro folder. This contains folder contains previous data and calculations from projects which have been analysed. If the project has been modified or was previously viewed in a previous version of the application, this database may need to be deleted to start afresh.
The folder may be found in this location on your machine:
C:Users\< User Name>\AppData\Local\FenestraPro.
All the files may be deleted here. New files will be created when the application is opened again in Revit.