When not to convert a file

If a file is legally or professionally significant, a signed contract, a certified translation, a court submission, a medical record, converting it can alter the layout or formatting in ways that affect its meaning or validity.

A converted document may look similar but contain subtle differences in spacing, line breaks, or typography that matter in a formal context. Where a document is paginated, a font substitution can shift content across a page boundary, and a clause that was on page four is now on page five, which matters if anything references it by page.

Digital signatures are a harder case. A signature applied to a PDF is cryptographically bound to that exact file. Any modification, including conversion, compression, or re-saving, breaks it. The converted file may open normally and show no obvious problem, while the signature it carried is now invalid.

Always verify legal or official documents before submitting a converted version. Where the document has been signed or certified, the safer answer is usually not to convert it at all, and to send the original instead.

Password-protected or encrypted files are another case where caution applies. FormatOS does not unlock or decrypt protected files, and does not recover passwords for files you cannot already open.

If you convert a protected PDF, the output may not preserve the original content correctly. Make sure you understand what a file contains and whether protections are in place before attempting a conversion.

Where you hold a password-protected archive and know the password, extraction is supported. Where you do not, no tool on this site will help, and that is deliberate.

Very large or high-resolution files can also be risky to convert without thought. A 200 MB video, a 300 DPI print-ready PDF, or a multi-gigabyte archive may produce unexpected results in a browser-based tool: either failing silently, timing out, or producing a degraded output.

This is a structural limit rather than a bug. Browser-based processing runs inside a browser tab, using that tab's memory. A file that comfortably exceeds the available memory will not process, and the failure may present as a stall rather than a clear error. Older devices and mobile browsers hit this limit sooner.

For production files at scale, purpose-built desktop software is often a better choice. FormatOS does not process video or audio at all, see supported formats for what is actually available.

Finally, if you are not sure what a file is or where it came from, it is worth understanding it before uploading it anywhere.

FormatOS is built for files you own. Uploading files you do not have the rights to use, or files from untrusted sources, is outside the intended use of the service and may expose you to legal risk. The Acceptable Use Policy sets out the boundary.

Where a file is an archive from an unfamiliar source, inspecting it lists the contents without extracting them, and the archive risk checker flags structural warning signs. Inspection is safer than extraction when you do not know what you are holding.

Ask three questions:

1. Does the exact appearance of this document carry weight? If it is signed, certified, filed, or will be relied on by someone else, treat conversion as a last resort.
2. Do I still have the original, somewhere I can get it back? If not, do not convert the only copy.
3. Can I check the output properly? If you cannot review the result (because it is long, or in a language you do not read, or full of numbers you cannot verify), the risk of an unnoticed error is real.

If any answer gives you pause, the right move is usually to send the original, or to have the conversion done by whoever is accountable for the document.