you don't keep the pdf archives files inside the sql archive do you?

The PDF documents, as well as other documents of any other type, are stored into a table with a FULLTEXT index accordingly to FTS specifications.
All other doc types are correctly indexed and FTS works, but for SumatraPDF iFilter. When it is the iFilter library referenced by FTS, new PDF documents are not indexed and no results are found when searching.

Thank you for your answer,
unfortunately Adobe iFilter has reached the End-Of-Support and I'm looking for a library that is still alive.

SumatraPDF iFilter should be working as I said I tested the current on latest windows 11 even using sandbox ,
however it works as designed within Windows Explorer search thus rules of engagement are

• the correct bit ness must match e.g. on a 64bit system you must have installed and thus registered the 64bit dll (@mmontelatici you seem to have done that)
• it can only search inside a pdf if explorer Isearching is on for compressed contents in the folder with the files (same as if you were looking for text in a zip)
• It will be slow, that is not a bug, it is that unless the index is stored gigantically by windows, then ALL the PDF files need time for unpacking to find one word. so for testing ensure the text can be read by copy and paste (often words are broken inside the pdf as single letter or corrupted characters)

here I list across many folder there are 70 files for searching

I ensure the index will search inside the content (there is no point in search otherwise but not all pdf have searchable content)

I then ask windows explorer to show me how many files contain Availability as a searchable word and the answer including duplicates is 7