We record for our internal issue about the Free SQL Server oversized, to backup our operations for checking in the future.
We know SQL Server Express edition has limited features. What we can do when we meet the file size issue are the following steps:
1: Delete some of data tables, please check here which we tried and confirm working well for SQL Server 2008R2;
Actually in this step we can select all generated result items, and they copy to working area to execute.
2: Restart related software in your system which connected the database (this step is optional, depends on how your software designing and implemented, but for our case, for our old software, we should restart one program which connected to database.)