I just cleaned my hard drive I have to reinstall my system and I tried to reinstall lightroom 6 and I have this error message "The specified serial number is valid but no eligible product n 'was found on this computer "have an idea? Olivier
Do you have an older version of LR?
That is what it is looking for as you have an Upgrade serial number. You should of gotten a second line in the dialog you typed in the serial number for LR 6 that asks for the serial from a previous version.
What OS are you using?
it is exactly this procedure you describe thank you very much for your help