Asking my Professor to create a Google Account to submit a Letter of Recommendation for me I requested a recommendation letter to a professor and he agreed to write one for me. However, the application  (a Google form) to which he needed to upload the letter required a Google account to sign in. He didn't have an account, so he emailed me what he should do, so I kindly told him that he needed to create one, detailing the steps he needed to take. This is when my professor emailed me back rather harshly, asking why he couldn't just submit using just his faculty email. I had to then email the program, and I was told to ask my professor to send the letter directly to the correspondent. 

I understand that this is not that big of an issue, but I would like to know whether it was wrongful of me to have asked my professor to create the Google account. How can I be more careful in the future so as to prevent negative responses?
My best guess, and just a guess, is that he was frustrated with the system that was required, rather than with you. It is probably a mistake for any admissions system to require an email address from a particular provider (unless it was for a job at Google, I suppose). 

I don't think you made an error, but if you want to ease the waters, go see him and apologize for the hassle of it all. It would probably be a mistake to just forget about it, but also a mistake to obsess over it. 

Such systems infuriate me, also. Such extra accounts are always a security/privacy issue.