Don't move your Windows user profiles folder to another drive

How to upgrade an old PC to Windows 10 - free

Windows enthusiasts just love to tweak their systems.

Through the years, the Windows community has built up an impressive body of tips and tricks designed to squeeze extra performance out of a stock installation of Windows. Unfortunately, some of those tweak have unintended consequences.

This week, as I was corresponding with early adopters of Windows 8.1, I ran into a perfect example of a tweak you shouldn't make. A reader posted this comment in the Talkback section of another post and, for good measure, emailed it to me as well:

What about this error?

"Sorry, it looks like this PC can't run Windows 8.1. This might be because the Users or Program Files folder is being redirected to another partition."

This affects a large number of desktop users with SSD system disks. If you have moved your Users folder to a secondary drive to conserve precious SSD disk space, Windows 8.1 will refuse to install.

This just seems like continuing evidence that desktop users (and open architecture) are an afterthought at Microsoft. Maybe, I read the wrong articles. Maybe, I believed the hype. Or maybe, it was just wishful thinking, but I thought that we were the users that Microsoft intended to accommodate with this new release.

I heard the same complaint from several other upgraders on Twitter who had experienced similar issues. And my response to all of them was the same: This is an unsupported configuration, and if you try it, you're just asking for trouble.

There is a supported way to move data folders off your system drive. You can relocate all the user-accessible folders from an individual user profile (Documents, Downloads, Music, Pictures, and so on), using a fully supported mechanism that I've previously documented. (See Windows 7 and SSDs: Cutting your system drive down to size.) You can even script the process if you want to make it simpler. That option solves most of the problem of big data files chewing up space on a small system drive without introducing any compatibility problems.

But diehard tweakers aren't satisfied with solving 90 percent of the problem. Why not move the entire Users folder, including all the hidden subfolders within it? At least one Twitter follower insisted, in a lengthy back-and-forth, that this configuration should work just fine and is fully supported.

Unfortunately, Microsoft begs to differ. Quite vehemently, in fact. Their advice is firm and crystal-clear: Don't even try to relocate user profiles to another partition or disk on a production system running Windows.

Most of the people who have made this tweak did so by following instructions from a third-party website. The tweak involves using Microsoft's enterprise deployment tools, including Sysprep, to install Windows. An answer file (in XML format) specifies a custom location for the Users folder. The specific variable used in that XML file is ProfilesDirectory.

Perhaps a look at the official documentation for that parameter would be useful:

ProfilesDirectory

The ProfilesDirectory setting specifies the path to the user profile folder.

Use this setting to move the user profile folder (typically %SYSTEMDRIVE%\Users) to another location during Setup or Sysprep. The destination path can be on a volume other than the system drive...

This setting can be used to keep system data separate from user data. If Windows is re-installed on the system volume, a user with administrative rights can manually recover data from this location.

Well, that sounds promising, doesn't it?

But keep reading, because immediately following that straightforward documentation are two blocks labeled Important and Caution.

Important

This setting should be used only in a test environment. By changing the default location of the user profile directories or program data folders to a volume other than the System volume, you will not be able to service your Windows installation. Any updates, fixes, or service packs will fail to be applied to the installation. Microsoft does not recommend that you change the location of the user profile directories or program data folders. [emphasis added]

"Only in a test environment" seems pretty straightforward to me. Don't try this on your production machines. Unfortunately, the third-party sites that recommend this tweak don't mention this caveat. In fact, they typically don't even link to the documentation.

And the next setting is even more explicit:

Caution

Using this setting to redirect folders to a drive other than the system volume blocks upgrades. Using ProfilesDirectory to point to a directory that is not the system volume will block SKU upgrades and upgrades to future versions of Windows. ... The servicing stack does not handle cross-volume transactions, and it blocks upgrades. [emphasis added]

Again, I'm not sure how this advice can be any more explicit. If you do this with a system running Windows 8.1, you won't be able to upgrade it to Windows 8.1 Pro. If you do it with Windows 7 Professional or Windows 8 Pro, you won't be able to upgrade to Windows 8.1, as my correspondent found out.

I thoroughly admire the resolve of Windows users who want to push the limits of the operating system. But with great power comes great responsibility. Including the responsibility to RTFM.