Troubleshooting: PDF Won't Open, or Says "Corrupted or Encrypted"

You pick a PDF file and the page says "Unable to open this file — it may be corrupted or encrypted." Don't panic — there are usually a handful of clear causes, and working through them in order will pinpoint the issue.

Cause 1: The file is genuinely encrypted

Some PDFs have an open password or a permissions password set. A tool that only edits text/images (with no decryption support) will simply error out on these. How to check: open the file in a different PDF reader that supports passwords (your OS's built-in preview tool, for example) and see if it prompts for one. If a password really is required, confirm it with whoever sent you the file, then decrypt it with the correct password before editing.

Cause 2: The file itself is corrupted

An interrupted download, a file truncated mid-transfer, a bad USB copy — any of these can leave a PDF incomplete. How to check: open the same file in a separate PDF reader (your browser's own built-in PDF viewer, for instance). If it also fails or errors there, the problem is almost certainly the file itself, and you'll need to get a fresh copy from the original source.

Cause 3: The file is too large, running out of memory

A PDF that's hundreds of MB or more (packed with high-resolution scanned images) needs a proportional amount of memory to load and parse in a browser — on a memory-constrained device, that load can fail or hang. How to check: close other memory-heavy tabs and apps and try again, or compress the images inside the PDF first with another tool.

Cause 4: An outdated browser

A modern web-based PDF editor relies on features only available in recent browser versions. How to check: update your browser to the latest version, or try a different mainstream browser (the latest Chrome, Edge, or Safari).

Still not working after all of this?

Check whether the file opens at all in any PDF reader whatsoever — if it fails even for basic reading, the problem is with the file itself, not any particular editor.