“You need to format the disk in drive E: before you can use it”: don’t format it

What the message means

The full text is “You need to format the disk in drive E: before you can use it. Do you want to format it?” with buttons for Format disk and Cancel. The drive letter will be whatever Windows assigned. It means Windows found the device but couldn’t recognise a usable file system on it. Typical causes:

• The file system is damaged, often after the drive was removed without “Safely Remove Hardware”, lost power, or the PC crashed during a write.
• The partition table or boot sector is damaged, so the volume shows as RAW. See RAW drive in Windows: files and fixes.
• The drive uses a file system Windows can’t read: APFS or HFS+ from a Mac, or ext4 from Linux or a Raspberry Pi. In that case the drive is fine and you should read it with something that understands that format.
• An SD card, USB stick or disk that is failing, or a bad cable or enclosure.

It is also what a brand-new, unformatted drive shows. If the drive is empty, Format is the correct answer. If it holds files, read on.

Safe checks that only look

1. Click Cancel. Unplug the drive, plug it into a different USB port directly on the PC (not a hub), and try a different cable. If you have another computer, try it there too.
2. Open Disk Management. Press Windows+X and choose Disk Management. Find the drive by its size. Just looking changes nothing.
3. Read what it says. “RAW” as the file system, “Unallocated”, “Not Initialized” or a Healthy partition with no letter each mean something different. Don’t click Initialize Disk on a disk that shows “Not Initialized” if it holds files you want: that writes a new partition table.
4. Optional, read-only: open Command Prompt as administrator and run diskpart, then list disk and list volume. These only print. Type exit to leave.
5. Is Windows seeing the whole size? A 1 TB drive that shows as a few megabytes, or doesn’t show a size at all, points at hardware or the controller, not the file system.

About chkdsk

Microsoft documents that running chkdsk E: without switches only reports status and makes no repairs, while /f, /r and other repair switches fix errors, which means they write to the drive (Microsoft Learn: chkdsk). On a mildly damaged NTFS volume that can be fine. On a failing drive, or when you have no other copy of the files, it is a risk you don’t need to take first. And on a drive Windows reports as RAW, chkdsk can’t help at all.

Copy your files off with Retrova

Retrova reads the drive directly and read-only, so the format prompt never comes into it. It understands NTFS, exFAT, FAT12/16/32, APFS, Mac OS Extended (HFS+), ext2/3/4, XFS and Btrfs, and shows you the partitions it finds. If the drive is BitLocker-encrypted, Retrova marks it Locked and opens it when you enter the password or the 48-digit recovery key.

1. Plug the drive in and open Retrova. On the home screen choose A drive won’t open. Retrova lists every drive and partition it can see, with the file system it detected.
2. Pick the drive or partition. Windows asks for administrator permission, because reading a disk directly needs it.
3. Browse and choose what you want back. If the file system is readable you see your original folders and file names, and you can preview photos, videos, PDFs and text before copying.
4. Choose a destination on a different drive with enough free space. Retrova never saves onto the drive it is reading.
5. Copy, then Verify. Files are written as temporary parts and renamed only when complete. When it finishes, run Verify to compare every copy with the original, byte for byte.

If no file system is recognised, or the one it finds is too damaged to list files, run Deep scan from I deleted something. Deep scan ignores the file system and searches the raw drive for the start of 72 known file types (photos including camera RAW, videos, audio, documents, archives, mail files and more). It only recovers files that were stored in one piece, and the original names and folders are lost: finds come back sorted by type with new names.

What Retrova can’t do: it can’t undelete files with their names on APFS, ext or other file systems (only NTFS, FAT and exFAT), can’t open an encrypted drive without its password or recovery key, can’t open the startup disk of a T2 or Apple silicon Mac away from that Mac, doesn’t handle RAID sets or phones, and can’t fix a drive with physical damage. Retrova’s builds aren’t signed or notarised yet, so macOS and Windows will show a warning the first time you open it.

After your files are copied and verified, formatting the drive is fine, and it may be what fixes it. In Disk Management, right-click the volume and choose Format. A quick format is enough. Note that on SSDs a format can issue TRIM, which can make old data unrecoverable, so do this last.

What not to do

Questions

Sources

• Microsoft Learn: chkdsk
• Microsoft Learn: diskpart

Related guides

• RAW drive in Windows: files and fixesWhy chkdsk says it is not available for RAW drives.
• USB device not recognized on Windows 11Fix the connection, then copy your files off safely.
• How to check a copy is perfect: verify files byte for byteCopies fail silently. Check recovered files against the original.
• Free USB drive recoveryDeleted, formatted or unreadable USB drive: what to do.