By the end of this lesson you will be able to
- Plug in, open and safely eject a USB drive on Ubuntu and Windows.
- Explain why safe ejection matters.
- Say what formatting does, and the checks to make before formatting anything.
- Choose between FAT32, exFAT, NTFS and ext4 for a simple purpose.
- Compare a USB drive, an external drive and cloud storage.
A USB drive is the easiest way to carry files between computers, hand them to a friend or keep a copy safe. It is also the easiest way to lose files, by pulling it out at the wrong moment or by formatting the wrong drive. This lesson shows you the habits that keep your data safe.
Kinds of removable storage
Removable storage is storage you can unplug and carry. A USB flash drive (pen drive) is a small stick with flash memory inside. An external drive is a larger drive in its own case, often with a cable and a lot more room: a portable hard disk or SSD. A memory card (an SD or microSD card) is a tiny flash card used in cameras and phones. All of them connect through a USB port or a card slot.
- USB flash driveTiny; carries documents and photos between computers.
- External driveLarge; a good place for backups of everything.
- Memory cardUsed in cameras and phones; may need a card reader.
Read this figure as text
A gallery of a USB flash drive, an external drive and a memory card with a short description of each.
USB flash drive: tiny, from a few GB to about 1 TB, good for moving documents between computers. External drive: larger, from 500 GB to several TB, a good place for backups. Memory card (SD or microSD): very small, used in cameras and phones, often needs a card reader or a card slot on the laptop.
Safe ejection
When you copy a file to a USB drive, the computer often does not write it straight away. It keeps some of the data waiting in memory and finishes the job in the background, so the progress bar can finish before the data is truly on the drive. If you pull the drive out too soon, the last files may be incomplete or the drive's contents may be damaged. Ejecting (also called safely removing) tells the computer to finish everything and then lets you know when it is safe to unplug.
- Step 1: Plug inInto a USB port
- Step 2: OpenIn Files or File Explorer
- Step 3: CopyWait for it to finish
- Step 4: EjectChoose Eject or Safely Remove
- Step 5: UnplugOnly after the message
Read this figure as text
A flow of five steps from plugging in a USB drive to unplugging it after ejecting.
Step 1: plug the drive into a USB port. Step 2: open it in the file manager. Step 3: copy files to or from it and wait until the copy finishes. Step 4: choose Eject, or Safely Remove, and wait for the message that it is safe. Step 5: only now pull the drive out.
Plug in, open and eject
On Ubuntu 24.04
Step 1: Plug in
Insert the drive into a USB port.
You should see: A new entry appears in the Files sidebar, with the name of the drive, and a notification may show.
Step 2: Open it
Click the drive's name in the sidebar.
You should see: Its files and folders are shown.
Step 3: Eject
Click the small eject icon next to the drive's name in the sidebar, or right-click it and choose Eject.
You should see: The drive vanishes from the sidebar. If a message says the drive is busy, close any windows or programs using it and try again.
On Windows 11
Step 1: Plug in
Insert the drive into a USB port.
You should see: A sound plays and the drive appears under This PC in File Explorer, with a letter such as D: or E:.
Step 2: Open it
Open File Explorer and double-click the drive.
You should see: Its files and folders are shown.
Step 3: Eject
In File Explorer, right-click the drive and choose Eject. You can also click the small USB icon in the taskbar's hidden-icons arrow and choose Eject for your device.
You should see: A notice says 'Safe to remove hardware' or the drive vanishes. Then unplug it.
Read-only devices
A device is read-only when you may look at its files but not change, add or delete any. Reasons include a physical switch on the side of an SD card (the LOCK switch), a drive that was prepared to be read-only, a CD or DVD that has been finished, or a drive from an unfinished eject that the system is protecting. If you see 'write protected' or 'read-only file system', check for a slide switch first, then eject and plug it back in.
Formatting: preparing a drive
A new drive, or one used on a different kind of computer, may need formatting. Formatting prepares a drive by setting up a file system, the filing method that keeps track of files, and it normally erases the existing contents. Think of knocking down all the shelves in a room and building new ones, so everything that was on the old shelves is lost to normal view.
The file system you choose decides where the drive works. The usual four are in the table below.
| File system | Works on | Notes |
|---|---|---|
| FAT32 | Windows, Ubuntu, macOS, cameras, many TVs | Very compatible but a single file cannot exceed 4 GB |
| exFAT | Windows, Ubuntu, macOS, many cameras | Good all-rounder for USB drives and cards; no 4 GB file limit |
| NTFS | Windows natively; Ubuntu can read and write it | The normal Windows system drive format; supports permissions and large files |
| ext4 | Linux (Ubuntu) | Normal Linux system format; Windows cannot read it without extra software |
- Will the drive be shared between Windows and Ubuntu (or a camera)?
- YesWill it hold single files over 4 GB?
- YesDo thisexFAT works on both and has no 4 GB limit.
- NoDo thisexFAT is the safer modern choice; FAT32 for very old gear.
- NoIs it only for Windows?
- YesDo thisNTFS is the native Windows format.
- NoDo thisext4 is the native Linux format.
- YesWill it hold single files over 4 GB?
Read this figure as text
A decision tree that asks whether the drive will be used on Windows and Ubuntu and what file size is needed, ending in a file system suggestion.
Start: will the drive be used with more than one kind of computer? If no and it is only for Ubuntu, use ext4. If no and only for Windows, use NTFS. If yes, will you store files bigger than 4 GB? If yes, use exFAT. If no, FAT32 or exFAT both work, and exFAT is the safer modern choice for most cases.
Where the Format command lives
Read these steps first; only carry them out on a spare, empty USB drive.
On Ubuntu 24.04
Step 1: Select the right drive
In Files, right-click the USB drive in the sidebar and choose Format…. Check the name and size in the window that opens.
You should see: A Format window asks for a volume name and a type, such as Compatible with all devices (FAT) or Compatible with modern systems (exFAT).
Step 2: Choose and confirm
Pick the type, name the drive and click Next. Read the warning that says everything will be erased and click Format only if you are sure.
You should see: After a short wait the drive is empty and ready to use.
On Windows 11
Step 1: Select the right drive
In File Explorer right-click the USB drive under This PC and choose Format…. Check the drive letter and capacity at the top of the window.
You should see: A Format dialog shows Capacity, File system, Volume label and Quick Format.
Step 2: Choose and confirm
Pick exFAT (or NTFS if only Windows will use it), keep Quick Format ticked, click Start and read the warning before pressing OK.
You should see: A message says 'Format Complete' and the drive is empty.
Physical or cloud?
Cloud storage keeps your files on a company's computers, reached over the internet. A USB drive keeps them in your hand. Neither is perfect. A USB drive can be lost, dropped or forgotten and does not need internet. Cloud files survive a lost laptop and can be reached from many devices, but you need an account, a connection and enough plan space, and you must trust the provider. Many people use both. You will return to this when you learn about backups.
- Works without internet
- One-off cost
- You physically hold your data
- Can be lost, stolen or damaged
Good for offline carrying and backups.
- Reachable from any device
- Survives a lost laptop
- Easy to share
- Needs account, internet and a plan
Good for access and sharing.
Read this figure as text
Two columns comparing USB drives and cloud storage on access, risk and cost.
USB drive: works without internet, you hold it in your hand, one-off purchase; but it can be lost, stolen or damaged and is easy to pull out wrongly. Cloud storage: reachable from any device with internet, survives loss of your laptop, easy to share; but needs an account and a connection, free space is limited and bigger plans cost money every month or year.
Common mistakes
✖ Instead of: Pulling the USB drive out as soon as the copy bar disappears.
✔ Do this: Always choose Eject first and wait for the confirmation or for the drive to vanish from the list.
✖ Instead of: Formatting a drive because a message told you to, without checking what is on it.
✔ Do this: Stop and check. Formatting erases data. Try another computer first, and ask for help if the files matter.
✖ Instead of: Using one USB drive as the only copy of important files.
✔ Do this: A copy must exist somewhere else too. USB drives are small and easy to lose or damage.
If something goes wrong
- The drive does not appear at all.
- Try another USB port, then another cable (for external drives), then another computer. A card may need a card reader. If it does not show anywhere, the drive may have failed.
- 'This drive is write protected' or 'read-only file system'.
- Check for a lock switch on an SD card and slide it away from LOCK. Eject and reconnect. If the drive stays read-only, copy the files to another place and consider whether the drive is failing.
- Ubuntu says the drive is busy and cannot eject.
- Close file manager windows and programs that are using the drive, wait a few seconds and try again. Do not unplug it while copying.
- Files over 4 GB will not copy to the drive.
- The drive is probably FAT32. Back up its contents elsewhere and reformat it as exFAT, or use a different drive.
Key terms
- Memory card
- A small removable card that stores files such as photos and music.
- Safe eject
- Telling the computer to finish writing to a drive so you can unplug it without damaging files.
- Formatting
- Preparing a drive with a file system, which erases everything that was on it.
- exFAT
- A simple file system that Windows, Ubuntu, macOS and many cameras can all read and write, with no small file size limit.
- FAT32
- An old, very widely understood file system that cannot hold a single file larger than 4 GB.
- NTFS
- The standard file system that Windows uses on its main drive.
Practise it for real
Reading is not the same as being able to do it. Complete these on your own computer, then tick only what you have actually done. These ticks are your own honest record: nothing checks them for you.
Plug in and eject a spare USB drive
Use a spare USB drive or memory card with no important files. Plug it in and open it. Copy a small file onto it, then open the file from the drive to prove it copied. Eject it properly using the method for your system, wait for it to disappear, unplug it, plug it in again and check the file is still there.
Challenge: which format and why?
Without formatting anything, decide on a file system for each case and give one reason. (a) A USB stick shared between your Ubuntu laptop and a friend's Windows laptop, with some 6 GB video files. (b) A drive only ever used on Windows. (c) A card for a very old camera that only reads FAT32. Then write the three checks you would make before pressing Format.
Knowledge check
6 questions. You need 80% to pass. Mistakes here are part of learning, and you can retry as often as you like.
Summary
- USB drives, external drives and memory cards are removable storage.
- Always eject before unplugging so that waiting data is written.
- Formatting prepares a drive with a file system and erases its contents.
- exFAT works across Windows, Ubuntu and macOS; FAT32 has a 4 GB file limit.
- Use physical and cloud storage together, and never keep the only copy on a USB stick.
Checklist: can you do these?
Marking a lesson as read does not prove you can do it. Skills count as demonstrated when you pass the quiz (not yet) and complete the practical tasks (not yet).
Related lessons
References and further reading
Official sources for details that can change between versions.
- Ubuntu Desktop guide: removable drives (Ubuntu)
- Windows support (Microsoft)