What to do right now
- Files you cannot lose and no backup: recover first, then run CHKDSK.
- If Windows offers to scan and fix the drive, or says it must be formatted, cancel for now.
- If the drive clicks or has failing health values, create a drive image and recover from the image instead.
- CHKDSK first is fine when the drive is healthy and the data is backed up.
The safe order
Cancel the repair prompts for now
When Windows says there is a problem with the drive and offers Scan and fix, or says you need to format the disk before you can use it, close the message. Neither choice brings files back, and both change the drive.
Check the drive's health
Open Disk health & tools in FileFix Ultimate. If the drive is At risk, clicks or keeps disconnecting, use Create a drive image (skip bad sectors) to copy it to another disk, and work from the image from then on.
Recover to a different disk
Open Deleted file recovery, select the drive or the image and start a scan. It reads the drive without writing to it. Save the files you need to a different physical disk.
Open and check what you recovered
Open the important files from their new location. The report shows which ones passed validation and which are partial or unverified, so you know what still needs attention before you change anything on the original drive.
Then repair or reformat
Once the data is safe, run chkdsk X: /f from an administrator Command Prompt, with X being the drive letter, or reformat the drive. If errors keep coming back or the health status worsens, replace the drive instead of repairing it again.
What CHKDSK changes on the disk
CHKDSK checks the file system's own bookkeeping: the master file table on NTFS, the allocation table on FAT32 and exFAT, folder indexes and free-space records. When something does not add up, its job is to make the volume consistent and mountable again. It does that by deleting index entries that point to damaged records, freeing clusters it cannot account for, and turning orphaned pieces into numbered files such as FOUND.000\FILE0000.CHK.
The volume works again afterwards, but the records that tied file contents to names and folders may now be gone. A recovery scan run after that often finds the same data only through content signatures, with generic names and no folders. Run before CHKDSK, the same scan could often have read the original structure. If CHKDSK has already run, the guide on files missing after CHKDSK explains how to deal with FOUND.000 and CHK files.
When running CHKDSK first is fine
Plenty of CHKDSK runs are harmless. If a USB stick was pulled out without ejecting, the drive is healthy, and Windows only flags it as needing a check, a repair usually just clears the dirty flag. The same is true when every important file is already backed up.
Running chkdsk X: without /f on NTFS only reports problems and does not fix anything, so it is a reasonable way to see how bad things are. On a RAW drive CHKDSK usually stops with the message that it is not available for RAW drives, which is another sign to recover first and repair later.
Common mistakes
Clicking Scan and fix out of habit the moment Windows asks. Leaving CHKDSK /r running overnight on a drive that is already slow or clicking, which reads every sector and retries the weak ones for hours. Formatting because Windows said so, then hoping recovery will bring back the old folder tree. Running CHKDSK several times in a row in the hope that the next pass will find the missing files. And saving recovered files back onto the same damaged drive, which overwrites what was still recoverable.
When recovering first is not enough
- If CHKDSK or a format already ran, structures it rewrote cannot be undone; signature search may still find file contents without names.
- A drive with mechanical problems, such as clicking or not spinning up, needs a recovery lab rather than any software.
- A BitLocker drive can only be scanned after it is unlocked with its password or 48-digit recovery key.
- Recovery copies files out; it does not repair the drive so it can be used again.
How FileFix Ultimate helps
- Scans read-only, so the drive is left exactly as CHKDSK or Windows found it.
- Reads NTFS, FAT32 and exFAT records to recover names and folders where they survive, and finds lost partitions and RAW drives.
- Creates a drive image that skips bad sectors, so a weak drive is read once and then left alone.
- Blocks saving recovered files to the same volume and warns about another partition on the same disk.
- Free for personal use, with no limit on the amount you recover.
FileFix Ultimate is free for personal use, works offline and never writes to the drive you are recovering from. Business use needs a one-year licence per PC. Check the signature before you run it.
Frequently asked questions
Windows asks to scan and fix my USB drive. Should I click it?
If the drive holds files you have no other copy of, close the message and recover first. If everything on it is backed up, scanning and fixing is fine and often clears the warning.
Can CHKDSK be undone?
No. CHKDSK has no undo and does not keep a copy of what it changes. What it turned into CHK files can sometimes be identified by content, but deleted index entries are not restored.
Will recovery software fix the drive so I can keep using it?
No. FileFix Ultimate copies files to another disk and never writes to the source drive. After recovery you can run CHKDSK, reformat or replace the drive.
Is it safe to run CHKDSK on an SSD?
On a healthy SSD it is generally fine, because there is no surface to wear out. The order still matters: if the SSD holds files you need, recover first, because a repair can remove the records that point to them.