I need to know how to do the following in Mail (Thunderbird does this but I need to use Mail):
How do I color-code email in the inbox with different colors representing user-determined categories such as IMPORTANT, OFFICE, PERSONAL for example, so that I can then search by color to easily find mail in these categories?
Mail will let me flag important emails but the flags are too little to stand out and be easily seen. There are also no categories assigned to each color. I want to be able to look at my inbox, quickly search by color to find mail identified earlier as PERSONAL, for instance, so that I can then reply.
Sounds like what you want to do is to tag each message. Mail doesn't have tagging, though since you can do it in Photos and the Finder, I wouldn't be surprised if Apple added tags in some future version of Mail.
In the past I have used MailTags ( https://www.indev.ca/MailTags.html) and was pretty happy with it. But I ended up going with the Gmail-centric idea of just archiving everything and finding old emails with searches.
Another idea is to use Gmail instead of your ISP's email server. I highly recommend getting away from an ISP email system (http://macmost.com/five-reasons-not-to-use-your-isps-email-service.html).
With Gmail, you've got folders. But folders are actually labels. Labels are tags. So you are doing what you want if you use Gmail. The Mac Mail app only shows these labels as folders, but at least it shows them. So you can still create the labels in the web version of Gmail and then drag and drop messages into the folders that then match those labels. I haven't investigated it too much, but I think you can get a lot of tag-like functionality that way as long as you switched to Gmail.
Thanks, Gary, for taking the time to help! Tis very much appreciated.
Select an email message in the Inbox, press Command-Shift-C, select the color you want. That's it. The message will be blatantly highlighted in the color you selected.
Mel: Good idea, but I think Maralyn wants to be able to search by these tags.