Which repair mode should I choose?

Try Conservative first because it changes less. Use Deep rewrite if the repaired file still will not open or render correctly.

Can this remove a PDF password?

No. Encrypted or password-protected PDFs are not accepted, and the tool does not bypass access controls.

No. The tool can rebuild damaged PDF structures, but irretrievably missing objects or page streams cannot be restored.

Rebuild broken cross-reference tables and PDF structure with qpdf, or use a deeper Ghostscript rewrite for files that still fail to open.

Start conservatively with qpdf, then try a Ghostscript rewrite only when the file remains unusable.

Every result is checked again with qpdf and pdfinfo before it becomes downloadable.

Repair can rebuild damaged structure, but it cannot recreate page data that is already missing.

Which repair mode should I choose?: Try Conservative first because it changes less. Use Deep rewrite if the repaired file still will not open or render correctly.
Can this remove a PDF password?: No. Encrypted or password-protected PDFs are not accepted, and the tool does not bypass access controls.
Is successful recovery guaranteed?: No. The tool can rebuild damaged PDF structures, but irretrievably missing objects or page streams cannot be restored.