Access 2007 is newer version of Microsoft access. Access 2007 supports windows vista. As it is newer and better version, but it still has some bug. Normally we prefer to save or access database in offline folders. If we are using Access 2007 we should avoid this. Because in Access 2007 when you perform compact operation on corrupt files, sometimes it shows “Database may be deleted on compact”. When you get error on database file you use compact and repair utility. At the end of compact operation you may get this error or you may see a dialog to the effect that Access cannot delete the database as it is "read only", even though the database is not read-only. As you click ok you database is lost from your pc.
To get rid from this problem and improve the performance of Microsoft Access 2007, you should periodically defragment your hard disk. Whenever you get this dialogue box, leave box unanswered and immediately make a copy of your database using windows explorer so that in case your database is delete due to this operation, still you have a copy of your important database file. Worst case is that if your database has been deleted from PC, so how will you recover it. For this you have good access repair utility.