Error 205 occurs when there is a problem with the downloaded file, I would recommend you to try alternate network connections and also please review the settings of any installed software firewall or security software that may be intercepting the downloads.
I have been running all CC apps with no trouble until now. Acrobat DC will not run. It opens and then abruptly closes with an error message. It says to contact Adobe support with the reference error 205. Searching Adobe help yields no results. There is scant info on it on the web either - everything mostly points to an install error. Mine just shut down.