Since the import process end with a huge size (around 16 GB for data and 26 GB for log) MSSQL start using the auto growth to expand the DB file size which will take long time and in some cases the expanding will stop when the DB reach the maximum file size.
We can reduce the import time to 1 hour or less in very simple way. all what we need is to expand the DB file size before start importing the demo data, the following steps illustrate how we can do it: