There is a database file size limitation on versions of NetAnalysis using the Microsoft JET Red Database Engine. File size: 2 gigabytes minus the space needed for system objects.
Improvements in v1.53
As As data is imported into version 1.53, NetAnalysis checks the size of the workspace file. When it gets to approximately 1.8 GiB, NetAnalysis will prompt the user to save the workspace. The data is then imported into a second workspace and will monitor the size of the workspace during import. This is not an ideal situation as it means the data will be split across multiple workspaces.