The Scenario 360 personal geodatabase is stored in a CVAnalysis.mdb file. As you use your personal geodatabase, this file may become fragmented on your disk, resulting in a decrease in performance. In general, this will occur in personal geodatabases as their size increases over 250 MB. To improve database performance, the database should be compacted on a regular basis. Compacting will rearrange how the personal geodatabase is stored on disk, often reducing its size and improving performance.
For more information, see ArcMap Help.