Get your diagnostic running.

FileDoctor does not require installation, accounts, a file upload or a paid API. These are practical steps if a local test doesn't complete.

The file picker won't open

Use the Select or Drop button, which opens the browser's system file chooser. Check that the browser isn't in a restricted embedded view. On mobile, the chooser may show photo or document sources depending on the device. Keyboard users can focus the selector and press Enter or Space.

The file is too large

Each input must be 64 MB or less. For very large archives, do not upload them here—use reputable locally installed software or create a smaller copy before testing. The browser may need additional RAM when decompressing compressed data.

ZIP or GZIP validation is unavailable

Some methods depend on the browser's DecompressionStream implementation. Update the browser or try another modern browser. An unsupported compression method, encryption or decompression limit is not proof that the archive is healthy or damaged.

A repair download doesn't open

Never discard your original. Examine the diagnostic findings and any reported omitted records or unverified sections. Open the new copy using a reputable program that supports its format. For critical files, recover from a clean source or backup instead.

Can FileDoctor remove malware or recover missing bytes?

No. FileDoctor is a diagnostic and limited cleanup tool. Structural inspection doesn't constitute antivirus scanning, and missing content cannot be reconstructed from markers alone. Review the recovery safety checklist before making changes.

How do I report a problem?

Record the tool URL, browser name and version, operating system, approximate file size and exact error text. Do not send confidential files to third parties. We do not currently operate an upload-based support service.