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About this tool
Check that your backup files really do decrypt, extract and open before you need them.
The Backup Restore Verifier opens a ZIP backup in your browser and actually decompresses every entry with CRC32 checking on, so each file is reported as Readable, Directory, or Encrypted or unreadable along with its true uncompressed byte size. It is for anyone who keeps ZIP backups of photos, documents, exports or archives and has never confirmed that the archive still restores. The result is a per-entry table plus a count of how many files came back readable — a restore test rather than a file listing.
Open Backup Restore Verifier on AltFTool — it loads instantly in your browser.
Pick your .zip backup with the Local file(s) chooser — only the first selected file is processed, and its name is echoed under the field.
Press Run local workbench: JSZip loads the archive with CRC32 checking on and decompresses every entry to a byte array inside the tab.
Verified result reports how many readable file(s) came back, over a table naming each entry with its uncompressed size and a Readable, Directory or Encrypted or unreadable status.
Every non-directory entry is decompressed to a Uint8Array, so a corrupt deflate stream or a bad CRC32 shows up as unreadable instead of hiding behind a valid-looking central directory.
The table names each entry with its size and status, so a mostly-good archive with three broken files tells you exactly which three.
Entries that cannot be decoded are labelled Encrypted or unreadable rather than being silently skipped or counted as fine.
Select the ZIP and run the workbench — it decompresses every entry with CRC32 verification enabled, and any entry whose data fails to decode is listed as Encrypted or unreadable. The summary line tells you how many entries came back readable.
No. There is no password field, and standard ZIP encryption is not decrypted here, so encrypted members are reported as unreadable. Use the archiver that created the backup to test those with the password.
No. The archive is parsed by JSZip inside your browser tab and never leaves the device — nothing is sent to a server, which also means very large archives are limited by your available memory.
ZIP only. TAR, 7z, RAR, and disk-image formats are not parsed, and an encrypted or non-ZIP file will simply fail to load rather than producing a partial report.