If you look at the installation and system management document you will see guides on how to deal with data deletion :
Deleting Part of a Database
If you don’t want to do anything quite so drastic as deleting the entire database, there
are various other ways to delete information:
• To remove old information, use the Date Compress batch jobs. In the navigation
pane, click Administration, IT Administration, Data Deletion, Date Compression and
then click the relevant application area.
• To remove individual records, click Edit, Delete. There must be no open entries or
nonzero balances for the records you want to delete.
• To remove a company, click File, Company, Delete.
• If you have access to the development environment for Dynamics NAV, you can
delete individual objects. You can read about the development environment in the
Application Designer’s Guide.
• If you need to delete almost everything except a couple of objects, such as some
reports, you can save the objects by exporting them before you delete the database.
You can then click File, Database, Delete to delete the
Please have a look at it .