Microsoft today issued a public statement about its plans for OneDrive in Windows 10, and confirmed that they are removing the smart files functionality that debuted in Windows 8. Instead, the firm will provide some key smart files features over time, and will focus OneDrive on reliability, consistency and key usage scenarios. Here's a rundown of what's happening.

This one is going to require a bit of explanation. Please bear with me.

You can access your OneDrive cloud storage in a few basic ways, including:

Office. Newer versions of the Office apps integrate with OneDrive (and OneDrive for Business) so that you can save to OneDrive by default and browse your own

Web. Navigate to from any PC/Mac or mobile device to browse your files and folders.

Mobile app. Microsoft provides a mobile app version of OneDrive on all popular mobile platforms (Android, iOS) and on Windows 8+ and Windows Phone. These clients are basically app-based ways to browse your folders and files, and to download items to the device individually.

Sync clients.  This is what we see on the desktop in Windows and Mac. The difference between the sync clients and the mobile apps is that the former support sync. You can configure folders—or in Windows 8+ even individual files—to be available offline. And they'll always stay in sync. The other advantage of OneDrive in Windows 8+, however, is that Microsoft provides a feature called smart files (sometimes called placeholders). These files let you see everything that is in OneDrive through File Explorer, even the files and folders that are only available offline. And they include meta data so that search, and certain apps, can work with them normally. When you open a placeholder file, OneDrive downloads it first and then opens it in the correct application.

Because the sync client in Windows 8.1 is so much better than the sync clients in Windows 7 and Mac OS X—and is likewise superior to the separate sync client for OneDrive for Business in any of these platforms—I had hoped and expected that Microsoft would bring its functionality forward, both in Windows 10—which is obviously based on Windows 8.1—and on the Mac. And in OneDrive for Business, for that matter. And until the most recent build of the Windows 10 Technical Preview, it appeared it would be doing just that.

But Microsoft is not doing that. Instead, it is using a new version of the sync client that, in this initial build at least, looks and works like the one in Windows 7 (or the Mac). There are no smart files (placeholders). And you must instead use a "Choose what you want to sync" interface to manually decide which folders will be viewable on your PC and available offline. That is, you cannot see the files that are in OneDrive (but not your PC) and you cannot arbitrarily mark individual files to be available offline.

I described some initial problems with this sudden and unexpected change in Here's a Fix for Some OneDrive Problems in Windows Technical Preview Build 9879. But based on the outcry from power users—who love and use smart files—it was clear that Microsoft would need to address this issue. And today they did, on the Windows 10 User Voice site.

Here's what they are doing with OneDrive in Windows 10.

Smart files (placeholders) are going away. Instead of making OneDrive in Windows 10 work like it does in Windows 8.1, it will instead revert to the way the sync client works elsewhere. That is, it will use selective sync like it does in Windows 7 and the Mac.

Why? Three reasons:

1. Because many users found smart files confusing. They would see the smart file on their PC, assume that meant the underlying file was there, and then go offline (on a plane, whatever) and discover they could not open the file. Outrage ensues.

2. Compatibility reason. Some applications—like Adobe Lightroom—don't work well with placeholders.

3. Reliability. Microsoft says that sync reliability was not where it needed it to be.

A new focus. With OneDrive offering unlimited storage and Windows shipping on ever-smaller devices with tiny (8 GB to 16 GB) storage allotments, even the placeholder files could quickly fill up a device. So OneDrive is being reengineered for this new world and will focus on:

1. Reliability first.

2. Consistency. OneDrive and OneDrive for Business will use a single sync engine and will work more like it does in the mobile apps (where OneDrive and OneDrive for Business are now accessible from a single app rather than two separate apps).

3. Scale. OneDrive has to scale to unlimited storage regardless of which device type you're using.

More is coming before Windows 10 ships. Between now and the final release of Windows 10, Microsoft will add the ability to search all of your files on OneDrive, even those that aren't synced to your PC, from Windows Search, and access those files directly from the search results. And it will vaguely "solve for the scenario of having a large photo collection in the cloud but limited disk space on your PC."

More is coming after Windows 10 ships. Windows 10 is only a step down the road from the perspective of OneDrive, and Microsoft will improve OneDrive past that release. It is committing to "bringing back key features of placeholders." Not placeholders, they're gone. But key features. Again, vague, so we'll see what means.

I'm obviously not super-happy that Microsoft has removed smart files (placeholders) but I do understand how that feature was likely very confusing for a lot of users. And let's be honest: If the company can add some key missing features—like integrated access to files shared through OneDrive, which I understand to be coming—and let OneDrive for Business work more like OneDrive (consumer), this will be a win, overall. We'll see.