Q. What does the scanning / copying error "Cannot detect original size" mean?
Usually encountered when scanning or making copies of passports, ID cards, or open books, the error message "Cannot detect original size" occurs because the scanning sensor is failing to identify an object in one of the standard paper sizes, such as A4.
The user must specify the size of the document and area of the scanning bed that it's on. Ensure that your object is in the upper left corner of the glass, then press ‘Scan Settings.’ Select ‘Scan Size’ and then ‘Custom Size.' Estimate the size of your object in the X field (horizontal) and Y field (vertical).