All email that gets put in the Junk E-Mail folder automatically (presumably by the SPAM filter or Blacklist filter) is then deleted automatically. Thus, I am not able to screen that folder to determine if any of the filtered email is legit. What setting(s) can I change to prevent automatically deletion of junk mail?
eM Client does not automatically delete Junk messages. You can empty Trash on exit, but not Junk.
Maybe look at what other devices are connecting to the same account, or the settings in the web interface for your email account.
What I have noticed is that, as email is checked, some emails momentarily flow to the Junk folder (which I witness by seeing that folder counter goes from blank to 1 or more). Seconds later, the folder is empty. The only other device looking at my email is my iPhone (native mail client as well as Outlook for iPhone). It shows a folder called “junk” instead of “junk email.”
Also, is there a way to whitelist email addresses or domains in emClient?
Go to Menu > Tools > Rules and untick the Spam filter Rule. This is the only way eM Client has to detect messages marked as spam by your server. Also, if you have created any Blacklist Rules, untick those. Check that you have not created any other Rules that might be moving messages to Junk. When that is done, then there is no way eM Client can move messages to Junk.
eM Client does not delete messages from Junk unless you do it manually. Maybe disconnect your iPhone from the email account and see if there is any difference. Or contact your email provider. It is not unknown for them to have issues like that occasionally.
No, there is no whitelist for this purpose. If the address or domain is not added to a blacklist, then it will not be affected.
Different applications call the folder different things. In eM Client it is the Junk E-mail folder. In Thunderbird it is either Junk or Spam depending on whether you use UK or US English.