I installed the latest version (10.0.12) of the PDF24 Creator on my Win10 PC and found that its OCR tool could not recognize texts. I tested both English and Japanese files. It seems that the tool processed and output new files, but they do not contain any texts on their PDFs.
When I uploaded the same original PDF files to your site and tested the online OCR tool, it could recognize texts successfully.
Are there something wrong with my settings for my desktop version?
Next version brings some more fixes to the OCR tool. The new version will be released next week. Then we will see whether your problems are solved. If not, you can get back to us again. Sample file are also very helpful which can be sent to firstname.lastname@example.org so that we can do some testing.
Today I installed the latest version of pdf24 and still no OCR at all works. That means the document is "scanned" but not a single word is recognized. Document is Dutch, setting is Dutch. This time there is no indication, as far as I can see, of a crashing tesseract. I provided you a sample document.