Help when a tool says no

Before you write to us

Five minutes of checking on your side usually beats a day of email. Walk through this list first.

• Copy the exact message on screen. The wording matters: "This file is not a PDF" and "This PDF could not be opened" point at different faults with different fixes.
• Note the address of the tool page. Paste the full URL from the address bar, since each tool prints its own messages.
• Note your browser and operating system. Name and version are enough, for example Firefox 132 on Windows 11 or Safari on iOS 18.
• Note the rough size and page count. A 400-page scan that breaks a tab is a different case from a two-page letter that a tool refuses.
• Check the usual suspects below. A password prompt, a huge file, or a photo renamed to .pdf each has its own fix in the troubleshooting section.
• Keep the document to yourself. Do not attach it to your email. If a shareable sample would help, we will ask for one with nothing private in it.

Write to a person

Send your message to [email protected] in whatever language suits you best. Include the tool page address, the exact sentence from the screen, which browser and OS you use, and roughly how large the file is and how many pages it holds.

The message text is the one part we cannot do without. A description like "it did not work" gives a person nothing to trace, while the exact sentence on screen points straight at the cause.

This is a small project, so a person reads every email. Simple questions get quick answers; tangled cases, where one file fails and others pass, take longer while the cause is reproduced.

You can also use the same address to suggest a tool or a change. Say what job you were doing and where the current tools fell short. Ideas that fit the two house rules, never uploaded and never unchecked, get built first.

Fixes for the usual failures

Most emails land in one of these five buckets. Each has a fix you can apply right now.

• The file asks for a password. Run it through Unlock PDF with the password you already know, then feed the unlocked copy to the tool you meant to use. A password nobody knows cannot be recovered, guessed, or worked around here.
• The tab freezes or reloads on a huge file. The job runs on your device, so the ceiling is the memory your browser tab can claim. Split the file into parts with Organize pages first, or repeat the run on a computer with more memory to spare.
• The tool rejects the file at once. The file is probably not what the tool reads: a photo renamed to .pdf, or a HEIC photo where JPG was expected. The catalog below names each case; the Images to PDF family covers the photo side.
• The run finished but no download appeared. The result failed its own verification: a page or some text would have been lost, so the file was discarded instead of shipped. That refusal is the check doing its job, described on how it works.
• The output came out wrong. Pages in the wrong order, upside-down scans, or a file too heavy to send are all fixable after the fact: reorder in Organize pages, straighten with Rotate PDF, shrink with Compress PDF.

The file was turned away

What follows is the message catalog. Each quoted sentence is lifted word for word from the code that prints it. Find yours, then read its fix.

• This file is not a PDF. The opening bytes carry no PDF header, which is what a file renamed from .jpg to .pdf looks like from the inside. Confirm what the file really is; if it is a picture, Images to PDF is the tool you wanted.
• This PDF could not be opened. The header says PDF but the structure inside is broken beyond what the reader can guess. Repair a PDF rebuilds the cross-reference table and may bring the pages back.
• This PDF is too damaged to open. Truncated files cannot be repaired in this tab. Something cut the download or the copy short, so the file ends mid-document. Fetch the file again from its source. Bytes that never arrived cannot be rebuilt by any tool.
• Password-protected PDFs are not supported yet. Your chosen tool cannot read an encrypted file, and that limit is per tool, not per site. Open the file in Unlock PDF with the password you know, then run this tool on the copy it returns.
• That password did not open this PDF. The entry does not match this file. PDFGym does not recover or guess passwords and never tries; check for a typo or ask the sender.

The tool is waiting on you

• Choose at least two PDF files. Merging only starts with a pair: add a second file and the button wakes up.
• Choose at least one JPG or PNG image. The images-to-PDF tool reads JPG and PNG only.
• Images to PDF accepts JPG and PNG. iPhone photos belong to HEIC to PDF and scanner output to TIFF to PDF, including multi-page TIFF files.
• Enter page numbers such as 1, 3-5. The page box was left empty or holds something unreadable.
• A page number past the end. Your range names a page the document does not have. Keep numbers within the last page the tool shows.
• Select at least one item to remove. The privacy scan found metadata but nothing was ticked for removal.
• Enter a header, a footer, or both. The stamp tool needs some text to place on the page.
• Mark at least one region to redact. Nothing was marked, so there is nothing to destroy.

The run stopped before the end

• Page N is too large to draw at 300 DPI. Choose a lower resolution. The image that page would produce is bigger than the browser will allocate. Drop to 150 or 96 DPI and run it again.
• The stamp falls outside a page. Choose another position, offset or font size. The text would land off the paper on at least one page, so nothing was written anywhere.
• This font cannot write one or more characters. Use Latin text for this version. The stamp text holds characters the embedded font has no glyph for.
• This image has no usable dimensions. The image opened but reports a width or height of zero, so there is no page to build from it.
• The selected metadata is no longer present. The file changed between the scan and the strip. Run the scan again on the current file.