According to Microsoft UK's Eric Nelson, MSDE will not be supported on Windows Vista. Although Eric claims that his July 12, 2006 post wasn't the first to report this potentially calamitous news, he didn't provide links to any predecessor posts. Apparently, the "lack of support" extends to SQL Server 7.0 and 2000, but it's unlikely that anyone would run full server versions under a client OS.
There has been remarkably little reaction to Eric's or predecessor posts, if there are any earlier references. Google blog search returns a few post-July 12 hits on the subject; Technorati returned only old (200+ days) entries for a July 21 search on 'MSDE'—before uploading this post. As sharp-eyed as always, Mike Gunderloy picked up the story for "The Daily Grind" on July 14, 2006.
ISVs whose commercial applications depend on MSDE 1.0 or 2000 will be most affected by Microsoft having deprecated these two products to "downlevel purgatory." Users who attempt to install either product under Windows Vista Beta 2 appear to receive a warning message but can continue installation. It's not yet clear what will occur in the release version when users attempt to upgrade to Vista a Windows 2000 or XP client with MSDE installed.
Eric also mentioned in passing that the "Visual Basic 6 Development Environment will not be supported on Windows Vista," which Jacqueline Emigh reported in her February 21, 2006 article, "Microsoft's Upcoming Vista To Support Legacy VB6 Apps" for Microsoft's DevSource. This article quotes Jay Roxe, Microsoft's lead product manager for Visual Studio, as stating that Microsoft will extend mainstream support for the VB6 runtime ... by another six or seven years, through the end of the Vista lifecycle.
Microsoft TechNet published "Upgrading MSDE 2000 to SQL Server 2005 Express" (SP-1) on April 7, 2006. If you don't mind a cumbersome login process, you can watch "MSDN Webcast: Upgrading from MSDE to SQL Server 2005 Express Edition (Level 100)" by the white paper's author, Michael Otey.
Euan Garden addresses issues with SQL Server 7.0 and 2000 versions of the Data Transformation Service (DTS) Import/Export Wizard for copying tables from one server and database to another. Euan also offers recommendations for importing and exporting data with SQL Express, which doesn't include the DTS (now SQL Server Integration Services or SSIS) runtime. Euan's "SQL MythBusters – MSDE/SQL Express has a 5 concurrent user limit" post includes brief histories of MSDE 1.0 and 2000, plus SQL Express. MSDE 2000 users can copy their .mdf and .ldf files to a new \Data folder and attach them to an SQL Express instance.
It's ironic that Microsoft has been promising for years to move Exchange Server's data store from the (Blue) Jet-based Extensible Storage Engine (ESE) to SQL Server. According to eWeek's "Exchange Data Store Change Still in the Cards" article by Peter Galli, Microsoft "says it remains committed to unifying this with the SQL Server database store going forward. They just don't know exactly when yet." Exchange 2007 will continue to use Jet— a technology that Microsoft deprecated as of MSDE 2000's release—not SQL Server as its data store.*
* Note: [Updated 7/23/2006] On July 22, 2006 Euan Garden let me know in no uncertain terms that I was wrong to associate Exchange's Blue JET (Joint Engine Technology) engine with Access's and VB's Red JET engine. See my July 23, 2006 "Red vs. Blue JET Database API Confusion" post.Microsoft officially released SQL Express (SQLX) on November 7, 2005 and Windows Vista might release in January or February 2007. This means that Vista early adopters' window to convert from MSDE to SQLX would have been about a year, had Microsoft publicized future lack of MSDE support when releasing SQLX. However, the window now is reduced to about six months as a result of July's "stealth-mode" announcement. Not nice. Technorati: Databases, Windows Vista, MSDE, MSDE 1.0, MSDE 2000, MSSQL, SQL Server, SQL Server 7.0, SQL Server 2000, SQL Server 2005, SQL Server Express, SQLX, Exchange, Exchange Server, JET