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How to fix "CRC failed" / CRC error when extracting a ZIP

CRC Failed : wp-content/uploads/2024/05/report.pdf

Each file inside a ZIP stores a CRC-32 checksum, and after decompressing it the extractor got a different checksum, so the extracted data does not match what was originally packed. For encrypted archives this usually means a wrong password; for unencrypted ones it means bytes inside the archive were changed or damaged.

Also appears as: file #12: bad zipfile offset (local header sig): 4382910 · inflating: report.pdf bad CRC 4c1f2a90 (should be 9b03e7d1) · CRC failed in the encrypted file report.pdf. Corrupt file or wrong password. · Data Error in encrypted file. Wrong password? : report.pdf

Common causes

Wrong password on an encrypted archive (ZipCrypto cannot tell a wrong password apart from corrupt data)
A few bytes were corrupted in transfer, for example FTP ASCII mode altering line-ending bytes
Failing storage: a bad USB stick, SD card or disk sector damaged part of the archive
Faulty RAM or overclocking on the machine that created or extracts the archive
A buggy or interrupted backup tool wrote inconsistent data
Antivirus or a proxy modified the file during download

How to fix it

Rule out the password first. If the archive is encrypted, retype the password carefully (watch keyboard layout, Caps Lock and trailing spaces). Errors that hit every file usually mean a wrong password; errors on one or two files mean corruption.
Test the whole archive. Run unzip -t file.zip or 7z t file.zip to list exactly which entries fail. This tells you whether one file or the whole archive is affected.
Get a fresh copy. Download or copy the archive again, using binary mode for FTP/SFTP, and compare the SHA-256 hash with the source. Most CRC errors come from a single bad transfer.
Extract the good files. Extract with 7z x file.zip or WinRAR with 'Keep broken files' ticked. Every entry that passes its CRC check is intact; only the failing files need recovery.
Check the hardware. If fresh copies fail on the same machine but work elsewhere, run a disk check (chkdsk /f or smartctl) and a memory test (Windows Memory Diagnostic or memtest86).
Recreate the archive from source. If you still have the original files, build a new archive and test it with unzip -t before deleting anything.

Shell

# list every entry and report CRC failures
unzip -t backup.zip
7z t backup.zip

# compare with the source copy
sha256sum backup.zip

How to stop it happening again

Always transfer archives in binary mode and verify a SHA-256 hash afterwards
Keep a second copy of important backups on different storage
Store archive passwords in a password manager instead of retyping them

File2fix tools for this error

ZIP Integrity Validator →Corrupted ZIP Safe Recovery →Hash Generator (MD5/SHA) →

Frequently asked questions

How do I know if it is a wrong password or corruption?

With a wrong password nearly every encrypted file fails the CRC check. If most files extract fine and only one or two fail, the archive itself is damaged.

Can a file that fails the CRC check still be used?

Sometimes. Text files, CSVs and some images may be mostly readable with a small damaged section, but treat them as unreliable; databases, executables and compressed files are usually unusable.

Does a CRC error mean the archive has a virus?

No, CRC errors indicate damaged or mismatched data, not malware. Still, if the archive was modified in transit, scan it before use.

How to fix "CRC failed" / CRC error when extracting a ZIP

Common causes

How to fix it

How to stop it happening again

File2fix tools for this error

Frequently asked questions

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