You opened a form — probably a tax return, an immigration form, or something from a government department — and instead of the form you got this:
Nothing is broken, and it is not your computer. That page is a fallback the file carries for viewers that cannot open it — which is nearly all of them.
What it actually is
The file is a dynamic XFA form. XFA is a format Adobe built into LiveCycle Designer, where the real form is not drawn on the PDF page at all — it is an XML program stored inside the file, which the viewer is expected to run. That is how these forms grow extra rows when you add a dependant, or hide sections that do not apply to you.
The catch is that essentially only Adobe's own reader runs it. Chrome's built-in viewer, Safari's Preview on macOS, Firefox, Edge, and every web-based PDF tool show you the fallback page instead, because there is nothing else on the page to show.
XFA was removed from the PDF standard in 2017 and Adobe stopped supporting it in newer versions of Acrobat, so no new ones are being made. The ones already issued — Canadian CRA returns, several US immigration and Social Security forms, older tax paperwork in a number of countries — will be around for years.
Three things that work
- Open it in Adobe Acrobat Reader, on a desktop. This is the real answer. Reader is free, it runs the XFA layer, and the form behaves as its author intended. Download the file first and open it from Reader rather than clicking the link — clicking usually hands it back to your browser, which is where you started.
- Check whether a plain version exists. Many agencies publish both: a dynamic XFA form and an ordinary fillable PDF, sometimes labelled "print and fill" or "accessible version". It is worth thirty seconds on the source page, because an ordinary PDF will work in anything.
- Print it and fill it by hand, if it is one page and you are out of patience. Unglamorous, and sometimes the fastest route to a filed form.
What does not work, whatever the search results say
Converting an XFA form to a "normal" PDF does not preserve the form. The converters advertising this generally flatten it to a picture of a page — you get something that looks like the form and has no fields at all, which is worse than what you started with, because now it looks fillable and is not.
And to be straight about our own tool: FormFill cannot fill these either. It runs in your browser, and the XFA layer is not something a browser can write to. Rather than fill the visible page and hand you a file that looks complete and opens blank in Acrobat, FormFill detects these forms and refuses, telling you to use Adobe Reader.
We would rather say that here than have you find out after filing.
How to tell before you start
If the "Please wait" page appears in your browser but the file opens normally in
Adobe Reader, it is dynamic XFA. If it opens fine in both, it is an ordinary form — and
that is the kind FormFill was built for, including the ones whose fields have
meaningless internal names like topmostSubform[0].Page1[0].f1_01[0], and
the flat printed ones with no fields at all.
If it turns out to be an ordinary form after all — which is the common outcome — fill it here, free, in this browser, with nothing uploaded. If it really is dynamic XFA the page will say so and refuse, rather than hand you a file that looks complete and opens blank.