Thumbs.db is a system file that contains the thumbnail cache–a collection of thumbnail images for photos, documents, Web pages, and so on–for a particular folder.

WDB files are used in Windows Work Database, and since they are discontinued, you need to use one of these methods to open WDB files ...

How to Restore a SQL Database From a .MDF File. Computer database software such as Microsoft's SQL Server benefits all types of businesses, as it makes recordkeeping fast, flexible and secure.

Warnings When you import a spreadsheet into an OpenOffice.org database, you lose any text styling, number formatting, macro scripts or charts that you previously used to enhance the data.

And, due to stupidity, I deleted the DB file (s) hoping that you could force File History to "reattach" to that store, scan it, rebuild the DB and we could get on with life.