Symptoms

The orientation of the resulting document was improperly changed by FineReader PDF 15.
The document with the portrait orientation was changed to the landscape.

Cause

The cause of the issue may be the vertical text (rotated right or left) in the original document. And the program is correcting the orientation of the document towards this text. 

Resolution

In order to resolve the described issue, please do the following:

1. In FineReader PDF 15 go to the Tools menu > select Options...;
2. Select the Image Processing tab;
3. Find the Image preprocessing settings section > click Show custom settings;
4. Uncheck the Correct page orientation option > click OK;
5. Try to convert the PDF document again.