Fix STG_E_MEDIUMFULL 0x80030070 – Disk Space Error

This error pops up when Windows thinks your drive is full, even if it isn’t. The fix is usually to free up space, repair the volume, or check for hidden system files eating space.

When You’ll See This Error

You’re copying a file to an external USB drive or an SD card, and halfway through, Windows throws up a message: STG_E_MEDIUMFULL (0x80030070) – There is insufficient disk space to complete operation. Everything freezes. Maybe you’re trying to back up photos, move a project folder, or install software. The drive shows plenty of free space in File Explorer – 20GB free on a 64GB card – but the copy fails every time. I had a client last month whose entire print queue died because of this, trying to save scanned invoices to a network drive.

What’s Really Happening

The root cause isn’t always actual disk space. Windows reports the error when it can’t write to the volume due to one of three things:

True low disk space – The drive is genuinely full, but Windows might be showing free space that includes hidden system files or reserved space (like the Recycle Bin).
File system corruption – The volume’s file allocation table has errors, so Windows can’t properly track free space. This is common on older FAT32 drives or external drives that were yanked out without ejecting.
Cluster size mismatch – If you’re copying a file larger than the volume’s max file size (e.g., 4GB limit on FAT32), Windows throws this error even with space.

How to Fix It – Step by Step

Step 1: Check the Drive’s Real Free Space

Run Disk Cleanup to clear temp files and Recycle Bin. Open File Explorer, right-click the drive, choose Properties, then Disk Cleanup. Select Clean up system files too. I’ve seen 8GB of temp files hidden from File Explorer’s view.

Step 2: Run chkdsk to Repair Volume Errors

Open Command Prompt as Administrator. Run:

chkdsk X: /f /r

Replace X: with your drive letter. The /f flag fixes file system errors, /r locates bad sectors. This can take 30 minutes on a big external drive. It’s saved my bacon more than once when the error appeared on a network share.

Step 3: Format if It’s FAT32 and You Need Files Over 4GB

If the drive is FAT32 and your file is larger than 4GB (like a video file or a large zip archive), reformat to exFAT or NTFS. Warning: this erases all data. Right-click the drive in File Explorer, choose Format, pick exFAT (best for USB/SD cards) or NTFS (for external hard drives), and run a quick format.

Step 4: Check for Hidden System Files Eating Space

In File Explorer, enable Hidden items and Protected operating system files (unsafe to show). Look for a $Recycle.Bin folder or System Volume Information – these can hog gigabytes. You can’t delete them directly, but running Disk Cleanup with the Clean up system files option cleans them.

Step 5: Use Diskpart to Clean the Volume

If chkdsk doesn’t fix it, the volume may be corrupt at the partition level. Open Command Prompt as Admin, run diskpart, then:

list disk
select disk X
list volume
select volume Y
clean

Replace X and Y with your numbers. This erases everything on the drive, including partition info. Then create a new volume and format it.

What to Check If It Still Fails

If you’re still stuck:

Check the drive for hardware failure. Use CrystalDiskInfo to look for reallocated sectors or pending errors. I’ve had a client’s external drive that looked fine in Windows but had dozens of bad sectors – the error was the only symptom.
Disable antivirus scanning temporarily. Some security software can interfere with write operations, especially on removable drives.
Try a different USB port or cable. Poor power delivery or connection can cause write failures, especially on older USB 2.0 ports.
Check the drive’s file system compatibility with the device you’re using (like a camera or printer). Some devices only work with FAT32, but you can try exFAT with a quick test.

If none of this works, the drive is likely toast. Replace it. Don’t waste hours – I’ve spent too many afternoons trying to resurrect a dying drive. Sometimes the fix is $30 for a new one.