Start from the page numbers shown by the source PDF, not printed numbers inside the artwork. PDFRemove uses 1 for the first source page and accepts comma-separated single pages or ascending inclusive ranges. A plan such as 2, 5-7 removes four pages. The preview reports both four removed pages and the number that remain, so the destructive-looking choice is converted into an explicit copy plan before processing.
What strict means
Whitespace around commas and hyphens is allowed, but zero, negatives, descending ranges, duplicate pages, missing endpoints, decimals and pages beyond the document fail. The tool does not clip 8-12 to an eight-page source or silently merge 2-4, 4-6. Correct the expression until the preview matches the intended absence.
Check what remains
For N source pages and R unique removed pages, the retained count is N minus R. At least one page must remain. Count alone is not enough: write the expected retained sequence when order matters, then inspect the downloaded first page, every boundary around a removed range and the final page.
The result is a new PDF
PDFRemove does not edit the source container in place. It creates a blank PDF, copies the retained page objects in their original order and serializes a separate download. Document metadata, outlines, page labels, embedded files, portfolios, scripts, optional layers, tagged structure, PDF/A or PDF/X claims, usage rights, encryption, incremental revisions and digital signatures may not carry across. Forms, links, annotations, fonts and accessibility relationships can rely on document-level resources. Keep the source and never call the output signed, certified, archival, compliant or evidentiary merely because its visible pages look correct.