I am unable to download Adobe Photoshop Lightroom 6. I do not want a CC version. I have a serial number.
What version of LR is your serial number for?
LR 6 and LR CC are the same program and it just hides or shows features based on the local licensing environment (serial vs AdobeID sign-in). What you download is always a trial of CC that you can convert to the serial-number-licensed version by entering a LR 6 serial number.