My C drive is full but my other drive is empty — what do I do?
Move the big user folders and the large program libraries properly, not by dragging. Which things move safely, which need reinstalling, and which must stay put.
- Difficulty
- intermediate
- Time
- 1 hr
- Read
- 4 min
- Safety
- caution
Short answer
Move user folders first: Documents, Pictures, Downloads and especially anything large like a photo or video library, using the folder's own location setting so the system knows where it went. Then move game and media libraries using the launcher's built-in move function. Programs generally need uninstalling and reinstalling to the other drive rather than moving. The operating system itself and its own folders stay where they are.
This is the standard shape of a machine bought with a small fast system drive and a large second drive, and it is entirely solvable. The rule is that anything with a location setting can be moved with that setting, and anything without one needs reinstalling.
Safety
Step by step
- Find out what is actually filling the drive.Use a disk usage visualiser before moving anything. Often the answer is one folder — a games library, a video project, a photo library, a virtual machine — and moving that one thing solves it in twenty minutes.
- Move user folders using their location setting.Windows user folders have a location tab in their properties that moves the folder and updates every reference to it. macOS handles this differently and less flexibly, and the photo library is the main one that can be relocated by holding a key while opening the application.
- Move the photo and video libraries.These are usually the largest single item. Both major photo applications support keeping the library elsewhere and will find it if you point them at the new location. Do it through the application, not by dragging the library file.
- Move game and media libraries with the launcher.Game launchers have a built-in facility to add a library folder on another drive and move installed titles into it. It moves the files and updates the launcher's records. Never drag a game folder.
- Redirect downloads and other working folders.Change the browser's download location and any application that writes large scratch files — video editors, virtual machine software, backup software — to use the second drive by default. This stops the problem returning.
- Reinstall programs rather than moving them.Most desktop programs install to the system drive and record their location in system settings. Uninstall and reinstall, choosing the other drive during installation, for the large ones. Small programs are not worth the effort.
- Know what cannot move.The operating system, its own folders, and anything that must be present before the second drive is available. Programs that install system-level components will keep part of themselves on the system drive regardless.
- Consider mounting the second drive as a folder.A drive can be presented as a folder inside another drive rather than as a separate letter. It is a neat solution where one specific folder needs to be enormous and must appear to be in its usual place.
- Check the second drive is worth using for this.If the second drive is a slow mechanical drive and the first is an SSD, moving your working files there will make them noticeably slower to open. Move archives and libraries; keep current work on the fast drive.
If it doesn't work
Moved a program folder and it stopped working
Cause: The system's records still point at the old location — Fix: Move it back if you can, or uninstall and reinstall properly. There is no supported way to relocate an installed program by dragging.
Second drive does not appear at all
Cause: Not initialised, not formatted, not assigned a letter, or not connected — Fix: Check the disk management tool — a new drive often appears there as unallocated and needs initialising and formatting before it is usable.
Moved user folder but the drive is still full
Cause: The bulk was elsewhere — snapshots, update cache, a hidden application folder — Fix: Use a disk usage visualiser and address what it actually shows rather than what you expected.
Everything is slower after moving files to the second drive
Cause: The second drive is mechanical and the first was solid state — Fix: Move only archives and rarely-used libraries there, and keep current work on the fast drive. Consider replacing the mechanical drive with a larger SSD instead.
Questions people ask
Can I just make the C drive bigger?
If there is unallocated space next to it on the same physical drive, yes, using the disk management tool. You cannot extend a drive across two physical drives in any way that is safe for a home machine.
Is it worth moving the page file or swap?
Rarely, and only if the second drive is at least as fast. Moving it to a slower drive makes memory pressure worse, not better.
Should I just buy a bigger SSD?
Frequently the better answer. Cloning the system drive to a larger SSD removes the problem entirely rather than distributing it, and drives are cheap relative to the time this takes.