Your external SSD or hard drive was working normally through a USB-C hub.

Then the hub disconnected unexpectedly.

When the drive reconnects, Windows now shows:

RAW

or:

0 bytes

Maybe File Explorer asks you to format the disk, the volume no longer opens, or the drive appears in Disk Management but the files are inaccessible.

The first reaction should not be to format the drive.

A sudden disconnect can interrupt an active storage operation, but RAW and 0-byte symptoms do not all mean the same thing. A drive that still reports its correct physical capacity but shows a RAW volume points in a different direction from a drive that reports 0 bytes or repeatedly disappears.

The safest approach is:

Protect the data first. Diagnose second. Repair last.

The Data Preservation Ladder

Use these four stages in order:

Freeze
↓
Stop writing to the drive.

Verify
↓
Find out what Windows or macOS actually sees.

Rescue
↓
Copy or recover important files before repair.

Repair
↓
Only then consider CHKDSK, First Aid, or formatting.

Skipping directly to the last stage can make a recoverable storage problem harder to undo.

Stage 1 — Freeze: Stop Writing to the Drive

If the drive contains important files, stop using it for normal work.

Do not:

• Format the volume
• Initialize it
• Create a new partition
• Copy new files onto it
• Run several repair utilities one after another
• Repeatedly disconnect and reconnect it during active disk access

Microsoft warns that formatting a volume destroys data on the partition, and its CHKDSK documentation confirms that repair parameters such as /f modify file-system structures to correct errors.

If Windows displays:

“You need to format the disk before you can use it.”

choose Cancel while important data is still at risk.

The goal right now is not to make the disk writable again.

The goal is to determine whether your files are still recoverable.

Stage 2 — Verify: Does the Drive Still Report the Correct Capacity?

This is the most useful first clue.

On Windows

Open:

Start → Disk Management

Find the external drive by its physical size.

For example, a 1TB SSD should still appear roughly as a 1TB physical device.

Check whether Windows reports:

• RAW
• Healthy partition
• Unallocated
• 0 bytes
• No Media
• Correct capacity but no drive letter

Microsoft's Disk Management tool is designed to show disks, volumes, partitions, and their current state.

Now interpret the result carefully.

RAW and 0 bytes should therefore not be treated as identical symptoms.

Stage 3 — Remove the Hub From the Evidence

Before repairing the file system, determine whether the USB-C hub is still affecting detection.

Test:

External Drive → Computer Directly

rather than:

External Drive → USB-C Hub → Computer

Keep the same:

• Drive
• Storage cable
• Computer

If your laptop has only USB-C ports and the drive uses USB-A, a 5Gbps USB-C to USB 3.0 data adapter can provide a simple direct data-path test without routing the drive through another multiport hub. The current LENTION product page shows direct purchase availability and data transfer up to 5Gbps.

This is a diagnostic test—not a reason to keep reconnecting a failing drive repeatedly.

Direct connection shows the correct drive and files

Copy the important files immediately.

Then troubleshoot the hub, power, cable, or connection separately.

Direct connection still shows RAW

The problem now follows the drive rather than only the hub path.

Move to the data-rescue stage.

Direct connection still shows 0 bytes

Try another known-good storage cable and another computer once.

If the same drive continues to report an incorrect or zero capacity across different systems, file-system repair may not be the right first tool.

Stage 4 — Rescue: Copy Anything That Is Still Readable

If another computer, port, cable, or direct connection suddenly opens the drive normally, do not assume the problem has disappeared permanently.

Copy the important data first.

Prioritize:

1. Irreplaceable documents
2. Photos and videos
3. Current projects
4. Work files
5. Anything without another backup

Only after the important files are safe should you spend time proving exactly why the disconnection occurred.

If the drive instead disappears completely rather than remaining visible as RAW, use External SSD Not Detected Through USB-C Hub? Fix It Fast for the separate port, cable, mounting, data-path, and power checks. 

RAW but Correct Capacity: Be Careful With CHKDSK

Suppose Disk Management shows:

1TB physical drive → correct

but:

Volume → RAW

This points more toward the logical volume/file-system layer than a disk being physically reported as zero capacity.

You may be tempted to immediately run:

chkdsk X: /f

Do not make that the automatic first step when the data is irreplaceable.

Microsoft's official CHKDSK documentation explains that CHKDSK without repair parameters reports file-system status, while /f fixes logical disk errors. Microsoft also notes that file-system repairs can change disk structures and, in some FAT scenarios, data can be lost during repair.

If the files are valuable, the safer order is:

Backup/recovery → Repair → Reformat if necessary

rather than:

Repair first → Hope the files survive

If the drive disconnects during repair, stop and solve the connection problem before attempting another repair cycle.

0 Bytes Is a Different Warning Sign

Suppose a 2TB drive appears as:

0 bytes

or:

No Media

That is not the same as simply seeing a recognizable 2TB disk with a RAW file system.

Test:

Same drive → Different cable

then:

Same drive → Direct computer port

then:

Same drive → Another computer

If the correct capacity returns during one of those tests, investigate the original USB-C hub, enclosure connection, or cable.

If several computers continue to see zero or an obviously incorrect capacity, the drive or enclosure controller may require specialist attention.

Avoid repeatedly formatting or repartitioning a device when the system cannot even report its physical capacity consistently.

On Mac: The Equivalent Symptom May Look Different

macOS does not normally present the same Windows “RAW” label in Finder.

Instead, the drive may:

• Fail to mount
• Appear only in Disk Utility
• Show an unreadable-disk warning
• Display a volume that cannot be opened
• Trigger “Disk Not Ejected Properly”

Open:

Applications → Utilities → Disk Utility

then choose:

View → Show All Devices

Check whether macOS sees:

1. The physical drive
2. The expected capacity
3. The container/partition
4. The volume

Apple's Disk Utility First Aid guide recommends having a current backup before repairing a storage device, then running First Aid through the volumes, containers, and device as appropriate. Apple also recommends checking the cable, connections, and power when an external storage device is not visible.

Again, if the data matters, recover readable files before using repair operations whenever possible.

Did the Hub Disconnect During a File Transfer?

That detail matters.

If the disconnect occurred while:

• Copying a large folder
• Editing directly from the drive
• Running a backup
• Exporting video
• Moving files
• Writing database/project files

then the interruption happened while the file system may have been actively updating data or metadata.

Do not continue using an unstable hub connection for recovery work.

For Mac users who also see unsafe-ejection warnings, Disk Not Ejected Properly on Mac? Fix USB-C Hub Disconnects covers sleep/wake behavior, direct testing, power, cable, and repeated storage disconnects. 

After the Files Are Safe: Find Why the Drive Disconnected

Once important data is backed up or recovered, return to the original USB-C setup.

Test the hub with only the drive attached.

Remove:

• Second SSDs
• Webcams
• Capture cards
• Phones
• Card readers
• Other bus-powered USB devices

Then check:

Drive only → stable?

Add charger → stable?

Add other peripherals one at a time → stable?

USB-C hub storage disconnects can involve the cable, available power, host connection, enclosure, peripheral load, or the drive itself. LENTION's existing storage troubleshooting content also recommends comparing direct and hub connections before assuming the SSD itself has failed.

When a More Stable Powered Setup Makes Sense

Do not buy new hardware to try to recover a RAW disk.

Recover the files first.

But if you later prove that:

• The drive works directly
• The storage cable is good
• The drive repeatedly drops only through the hub
• The problem becomes worse with several peripherals attached
• Adding stable PD power improves the connection

then a powered workstation setup may be more appropriate.

A USB-C docking station with 100W Power Pass-Through and dedicated USB 3.0 ports provides power pass-through plus three USB 3.0 and two USB 2.0 ports; LENTION specifically notes that the charging input can also provide additional power to attached USB peripherals when several high-power devices are connected. Its current product page shows Add to cart.

This should be treated as a future connection-stability choice—not as a repair tool for an already-damaged file system.

Repair or Format? Use This Gate

Do not decide based only on the word “RAW.”

Formatting should be at the end of this process, not the beginning. Microsoft explicitly warns that formatting an existing volume destroys the data on that partition.

Final Verdict

If an external drive shows RAW or 0 bytes after a USB-C hub disconnects, the most important mistake to avoid is trying to “fix” the disk before deciding whether the data needs to be saved.

Use the Data Preservation Ladder:

Freeze
→ Stop writing, formatting, or repartitioning.

Verify
→ Check the physical capacity and volume state.

Rescue
→ Direct-connect and copy/recover important files.

Repair
→ Use CHKDSK, First Aid, or formatting only after the data risk is understood.

Remember:

Correct capacity + RAW
→ Think file system or partition structure.

0 bytes / No Media
→ Check connection, enclosure, controller, or hardware.

Direct works but hub fails
→ Troubleshoot the USB-C path.

Drive keeps dropping during repair
→ Stop and stabilize the connection first.

The key rule is:

When the data matters, recovery comes before repair.

FAQ

Why did my external drive become RAW after a USB-C hub disconnected?

An interrupted connection can coincide with file-system or volume problems, especially during an active write, but RAW does not prove one universal cause. First check whether the physical disk still reports the correct capacity and whether the same result appears through a direct connection.

Should I format a RAW external drive?

Not if it contains files you still need. Microsoft warns that formatting a volume destroys the data on that partition. Back up or recover important data before formatting.

Should I run CHKDSK /f immediately?

Not automatically when irreplaceable data is involved. Microsoft's CHKDSK documentation confirms that /f repairs logical file-system errors and modifies the disk as part of the repair process. Consider recovery or backup first.

What does it mean if my external drive shows 0 bytes?

If the expected physical capacity disappears, test another cable, direct computer connection, and another computer. A persistent zero or incorrect capacity points away from a simple drive-letter problem and deserves hardware/controller investigation.

Why does the drive work directly but fail through the USB-C hub?

That result makes the hub path more suspicious. Check the data port, cable, peripheral load, host connection, and available power before trusting the setup for additional writes.

Can Disk Utility repair the drive on Mac?

Apple says Disk Utility First Aid can check and repair formatting and directory-structure errors. Apple recommends having a current backup before running repair operations.