You open "This PC" and there it is — your D drive, E drive, or external hard drive, sitting right where it should be. The drive letter shows up. The capacity looks fine. But you double-click it and nothing happens.
Or worse — Windows throws an error: "Location is not
available," "The parameter is incorrect," "The file or
directory is corrupted and unreadable." Maybe you get the dreaded
"You need to format the disk before you can use it." Or sometimes
there's no error at all. You just double-click, the cursor starts spinning, and
your whole machine grinds to a halt.
I see this all the time. And the first thing most people do
is panic — they assume the drive is dead, hit "Format," or start
running random repair commands. If there's anything important on that drive —
photos, work documents, years of files — that's the worst thing you can do.
Here's the thing: an inaccessible partition does not mean
your data is gone. The drive is still showing up. The computer still sees
it. The problem is almost certainly in the file system, the partition table, or
the file directory — not in the data itself. In most cases, as long as you
haven't written new data to the drive or suffered serious physical damage, you
can get those files back.
What's actually going on when a drive won't open?
A healthy drive shows up in "This PC" with a drive
letter, and you double-click to browse its contents. When double-clicking
doesn't work but the drive is still visible, that tells you the physical
connection is fine — the OS detected the drive. What it can't do is read the
file system.
Think of it this way: the data on your drive isn't just
dumped there randomly. The OS relies on an index — partition tables, boot
records, the MFT (Master File Table) in NTFS, or the FAT table in FAT32 — to
find and read files. When those structures get damaged, the OS can see the
drive exists, it knows there's a partition on it, but it can't make sense of
the contents. That's what produces all those error messages.
The specific error you see actually tells you a lot about
what's broken and how bad it is.
"You need to format the disk before you can use
it"
This one's the most common. Full message: "You need
to format the disk in drive X: before you can use it. Do you want to format
it?"
What it means: the OS found the partition and tried to read
it, but the boot sector (DBR) is damaged or missing. Without that, the system
can't identify the file system type, so it suggests formatting.
Click Cancel. Do not format. Quick format rebuilds
the boot sector and file index. The actual data sectors might still be intact,
but the directory structure pointing to your files gets overwritten. Even if
you recover data afterward, you'll likely lose file names and folder hierarchy.
Skip the format, and there's a much better chance everything comes back clean.
"The file or directory is corrupted and
unreadable"
Usually: "Location is not available. X:\ is not
accessible. The file or directory is corrupted and unreadable."
This typically means the MFT (in NTFS) or FAT table (in
FAT32) is corrupted. The good news — relatively speaking — is that the OS still
recognizes the file system type. The framework is there; parts of the index are
just broken. This is actually a slightly better situation than the
"format" prompt.
"The parameter is incorrect"
The OS is reading parameters from the partition — sectors
per cluster, partition start offset, things like that — and the values don't
make sense. Could be a corrupted partition table, or bad sectors returning
garbage data when the system tries to read those parameters.
Double-click → spinning cursor → system freeze
This one's more concerning. The file explorer hangs, the
mouse stutters, the whole PC bogs down. What's happening: the OS is stuck in a
loop, retrying failed reads over and over. This usually points to a physical
problem — bad sectors on the drive.
Stop clicking. Don't keep double-clicking. Don't
force-restart. Every read attempt puts more stress on the damaged area and can
make things worse.
Disk Management shows "RAW"
Open Disk Management (right-click "This PC" →
Manage → Disk Management) and you notice a partition that should be NTFS or
FAT32 is now labeled RAW.
RAW isn't a real file system format. It's just the OS saying
"I don't recognize this." The boot sector might be gone, the
partition type ID in the partition table might be wrong, or critical metadata
areas are corrupted.
Don't let "RAW" scare you. Data recovery software
can scan the drive's raw data directly, bypassing whatever the OS thinks about
the file system.
Why does this happen?
The usual suspects:
- Sudden
power loss or yanking out a USB cable. If the drive was mid-write when
power died, or you unplugged an external drive without "Safely Remove
Hardware," metadata may have only been half-written. Next time you
plug it in — won't open.
- Malware.
Some viruses go after partition tables, boot records, or file allocation
tables directly.
- Bad
sectors. If the area storing file system metadata develops bad
sectors, the OS can't read the critical structures. More common on older
mechanical drives that have been running for years.
- Botched
partition operations. Interrupted a resize or merge in a partitioning
tool? Accidentally deleted a partition? That'll do it.
- Error
accumulation. Small file system errors pile up over time if you never
run disk checks. Then one day you boot up and the drive just... doesn't
open.
- Firmware
bugs. Certain drive models from certain manufacturers have known
firmware issues that can cause this. Not common, but it happens.
Can I just format it and start over?
No.
I know the OS is literally telling you to format. I know it
feels like the obvious move. But formatting rebuilds the file system's index.
Your data sectors are probably still fine, but the map pointing to your files
gets overwritten. After formatting, recovery software might find your files,
but they'll come back with names like file0001.jpg, file0002.docx, all dumped
into a flat list with no folder structure.
Recover first. Save to a different drive. Confirm the data's
good. Then format.
What about running CHKDSK?
This is where I see people make the most costly mistakes.
CHKDSK is a file system repair tool. It is not a data
recovery tool. The distinction matters.
Here's what CHKDSK actually does: it scans the file system
for inconsistencies and "fixes" them — by modifying the metadata
directly on the drive. If it decides a file's index is broken, it might
truncate or delete that file. If it thinks a directory is damaged, it'll dump
everything into a folder called FOUND.000 and rename all the files with .CHK
extensions.
For the file system, this might be helpful. For your data,
it can be destructive. And if there are bad sectors on the drive, CHKDSK
hammering at those bad spots can cause them to spread — turning recoverable
data into unrecoverable data.
The right move: use data recovery software to pull
all the data off first. Save it somewhere else. Verify it. Then either format
the drive or let CHKDSK do its thing — at that point, you've got nothing to
lose.
If you've already run CHKDSK, don't panic. The data isn't
necessarily gone. But file names and directory structure will probably take a
hit.
How to recover with DiskGenius — step by step
DiskGenius handles inaccessible partitions, format prompts,
and RAW file systems well. Here's the process I recommend:
Step 1: Just try browsing the files.
Open DiskGenius. Click the inaccessible partition. Switch to
the Files tab.
Sometimes Windows Explorer can't open a partition but
DiskGenius can — it has a more robust file system parser and handles damaged
structures better. If you can see the files, preview them to check integrity,
and copy them to another drive. Done.
Step 2: "Load Current Partition Intelligently"
Right-click the partition → Load Current Partition Intelligently.
For milder damage, this will pull up the full original
directory — file names, folder structure, everything intact. Preview your files
to make sure they're actually readable, then export to a different drive.
If it doesn't find what you need, the damage is more
serious. Move on to Step 3.
Step 3: Full deep scan with "File Recovery."
Select the partition → click File Recovery →
click Start in the dialog.
The software scans the entire partition, using both the
remaining file system data and raw data signatures to locate files. This takes
longer but goes much deeper.
When it finishes, preview before you celebrate. A
file name in the list doesn't mean the file is intact. Double-click photos to
see if they display. Open documents. Play videos. That's how you know.
Select what's good → right-click → Copy to Specified
Folder → save to a different hard drive.
One thing to note: this is a case of a damaged partition,
not a missing partition. The partition is still there — it's just
broken. The "Search Partitions" feature isn't what you need here.
Now the Copy Sectors window opens.
Wait for the scanning to complete, and you will receive a report when it gets finished. If the disk contains bad sectors, you can click Repair button to try repairing them.
