When starting to type an email address, eM Client will complete the address (as expected). However, I have one example where it prefixes it with what looks like an alias. However, I cannot find where the alias comes from. It is not in the contacts entry for that person.
We offer address suggestions from your contacts, but also from the recipient history and from messages in your Sent folders.
You can manage the recipient history (delete the entry or clear the whole history) and disable the Sent folder suggestions in Menu > Settings > Mail > Compose > Email Address Suggestions.
It is certainly possible to manage the recipient history as described but the address suggestions from my contacts list are inconsistent. Addresses I know are there in Contacts are not showing up when I start typing their address and I can’t see how to correct this.
Could be the account contacts that are not appearing “are not selected” in the dropdown.
Click To: in the compose window, and then click the dropdown on the right of “Folder” and make sure you have selected either All Contacts or the Specific account contacts you want, which will then appear when you type email addresses.