I keep emailing work colleagues at their home email address...

[The English Hacker]

I use my HTC One tied to my corporate email account. On numerous occasions I have emailed colleagues and if I'm not paying close attention to their address it puts in their personal email address rather than their work one. Primarily this seems to happen when I have a weak signal. Note that in most cases I don't actually have their personal address in "People". Therefore I assume it's being pulled from their social media accounts.

How can I prevent this from happening?

 

[VidJunky]

If you go into People and link their contact with their social networking account you can then set a primary email just as you would a primary phone number. Since it sounds like you do more communicating for business than leisure that may be the better alternative.

I don't think your signal has much to do with this issue it likely has more to do with how you start off their address.