To amplify a little bit, @eddy72:
When you update the program, the installation process replaces the older version of the application itself. But the application contains no data about your business(es). Business data is contained in business data files, located in an application data folder. The program calls the data when you run it. If you have multiple businesses, and switch between them, it will call from different business data files. The application data folder also contains an index file. The program looks to that index file to see what business files you have and where they are.
Newer versions of the program automatically convert older business data files to current formats whenever that is needed. It places the converted files back into the same application data folder. Importantly, it also modifies the index file so when you open that particular business it calls data from the converted file rather than the old one. You should not need to do anything to reimport.
Now, suppose you had a computer problem and lost the drive where the application data folder was stored. Then you would need to install the program on a new machine (or drive) and use the Add Business process to restore from a backup. During that restoration, Manager should also convert the identified backup file to a new format, if required.
If none of the information you’ve been provided helps resolve your problem, you need to provide more specific information about your hardware and software situation. What did you do, in what order? How far did you get? Could you open the updated program at all?