Diagnose a checksum mismatch before repeating the download

Check which result is being compared

A mismatch means none of the generated results equals the expected value you supplied. It does not explain the cause. If an algorithm could not start in your browser, its missing result cannot verify the reference; inspect any availability notice first.

Compare the publisher's filename, version, operating system and processor architecture with the selected file. A ZIP, an installer and the unpacked program are different inputs. Repacking an archive can also change its bytes even if the files visible inside look unchanged.

Do not infer the algorithm from its length

SHA-256, SHA3-256 and Keccak-256 can each produce 64 hexadecimal characters while disagreeing on the same input because they are different algorithms. Use the name attached to the reference rather than choosing a menu entry based only on digest length.

If you change the selected algorithm or input, generate fresh results and then paste the expected digest again. LocalHash clears the earlier comparison when the calculation inputs change.

Paste only the hexadecimal digest

LocalHash ignores surrounding whitespace, treats uppercase and lowercase hexadecimal letters alike and accepts a leading 0x. It does not strip a filename, remove spaces inside the value or decode Base64. A full checksum-file line often contains more than the digest field.

In the illustrative record below, copy only the characters before the spacing and filename. If another system reports Base64, regenerate its digest as hexadecimal or convert that representation before comparing it.

Checksum-file record:
ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad  example.txt

Paste only:
ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad

Check the bytes before trying another source

In Text mode, inspect a final newline, trailing spaces and the encoding used at the other end. Use File mode when the reference was made from a saved file. For a cloud-drive placeholder, download a complete local copy before selecting it.

After confirming the reference and input, obtain a fresh copy from the official source and calculate again. If the same mismatch persists, retain the unexpected result and ask the publisher to check the reference. Do not substitute a value from an unrelated mirror merely because it matches.

There is no close-enough digest. A value that differs by one character is still a mismatch; changing only hexadecimal letter case is not.

1. Confirm that the required algorithm produced a result.
2. Match the release, filename and package type.
3. Remove labels, filenames and internal separators from the pasted digest.
4. Check text encoding or verify that the selected download is complete.
5. Retry from the official source only after these comparisons identify what needs changing.

References and further checks

• Keccak designers: Algorithm overview
• NIST: SHA-2 and SHA-3 families