Upload Requirements Checklist: Why Portals Reject Documents

An upload form that says "invalid file" costs more time than the document did. Most rejections come from a short list of technical conditions, and almost all of them can be read from the file before you upload it. This checklist covers what portals ask for, how each condition is measured, and where the number you see can differ from the number the portal sees.

File size

Limits are given in KB or MB, and portals do not agree on what that means: 1 MB can be 1,000,000 or 1,048,576 bytes. If your file is within a few per cent of the limit, make it smaller than it needs to be. For PDFs, Compress PDF reduces size; for photos, Compress Image does.

Format by content

A file's type is what it contains, not what its name says. Renaming a Word file to .pdf does not make it a PDF, and portals that look inside will refuse it. Some also reject a PDF with the extension in capitals or a double extension. Check the format by content, and keep file names short, plain and free of spaces if the portal says so.

Pages, paper size and orientation

PDF page size is stored in points (1/72 inch) per page, together with a rotation flag. A4 is 595 by 842 points (210 by 297 mm) and US Letter 612 by 792, so "close to A4" is not A4 for a strict portal. A document can mix sizes and orientations. A scan taken sideways and rotated by a flag is a classic source of "landscape" pages. The PDF Page Size Analyzer lists every page, and the PDF Page Resizer can bring them to one size. If the portal limits pages, Extract PDF Pages keeps the ones you need.

Passwords and permissions

A PDF that needs a password to open cannot be read by a portal. A PDF that opens normally but is encrypted with an owner password, for example to prevent printing, is still rejected by some systems. Remove the encryption before uploading if the portal says "no password".

Text layer

A scan is a picture. When a portal asks for searchable text, it needs a text layer from OCR. Check that the text is there and that it copies correctly with the PDF Copy-Paste Text Health Checker, and that the hidden layer is aligned with the PDF OCR Layer Alignment Checker.

Resolution

Resolution has two meanings. In a JPEG or PNG header it is a density tag that says how large the picture is meant to print; many files have none. In a PDF, the effective resolution of a picture is its pixels divided by the size it is drawn at. A portal asking for 200 dpi or more is asking about the second; if only the tag is missing, the Image DPI Changer sets it without touching the pixels. Width and height in pixels are a separate requirement for photos.

Metadata, scripts and attachments

Some portals refuse PDFs with JavaScript, attachments or form scripts, and some ask that files carry no personal metadata. Check with the PDF Active Content Scanner and the PDF Metadata Viewer & Remover, and remove GPS data from photos with the Image Metadata Remover.

One check for all of it

The Document Upload Preflight Checker takes the numbers from the portal's instructions, checks your file locally against all of them, and answers PASS, WARNING or FAIL for each. It cannot know what a given portal enforces, so a PASS is not an acceptance, and the portal's own instructions always win. If the file will go to many people instead of one portal, see how to check a PDF before sharing it.