Luke Lindsay wants to change his drive letters. But he’s worried about the problems it may cause.

Drive letters were part of the PC environment before they were called PCs. My first computer ran CP/M, and the two floppy drives were A: and B:. We’re still using drive letters today, but they’re more pliable—and they can also create more problems.

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As a test before writing this article, I changed my D: partition—the one where I keep my library files—to F:. Nothing worked. Windows couldn’t find my files. It couldn’t run Skype. Carbonite froze. Even my wallpaper went black. Changing the drive back to D: and finding everything good again was a big relief.

Windows has a good reason for giving you a stern warning before it changes a drive letter.

The problems come when Windows and other programs expect a file in a particular place. If Microsoft Word expects my normal.dotx template file to be at D:\Lincoln\AppData\Roaming\Microsoft\Templates, and it discovers that there’s no D: at all, it won’t know to look in F:\Lincoln\AppData\Roaming\Microsoft\Templates.

Obviously, changing drive C:’s letter would be a disaster. Windows wouldn't be able to find itself.

There are drives whose letter you can safely change. If a partition contains only data files that you rarely use, changing the drive letter may cause an occasional annoyance but rarely anything worse. External drives' letters can almost always be changed without problems.

To change a drive letter, use the search tool in your version of Windows to search for partitions(don’t miss that s). Select Create and format hard disk partitions.

This brings up the Disk Management program. Right-click the partition you want to change, and select Change Drive Letter and Paths. 

In the resulting dialog box, click Change. Then select an available drive letter and click OK.

And, of course, click Yes at the warning...assuming you’re sure that it won’t cause a disaster.