When I highlight an email, and pull up from the bottom, the window opens, but is always saying "No message selected"! Obviously, I have selected a message, so why won't it work as it should? This only began happening after upgrading from Mojave to Catalina.
iMac 27″ 5K, macOS 10.15
Hi there Saxman,
We understand you're seeing a "No Message selected" alert when dragging a message.
To confirm, are you using Column view? Follow the steps in this article: Read emails in Mail on Mac
"Change how emails are shown
In the Mail app 
on your Mac, do any of the following:
Try adjusting your Preview, for example does this occur using Side Preview?
Does this occur with every email? Or specific ones? does it happen constantly or is it intermittent?
See if the same thing occurs in safe mode and another user account:
How to use safe mode on your Mac
Set up users, guests, and groups on Mac
Cheers!
Hi there Saxman,
We understand you're seeing a "No Message selected" alert when dragging a message.
To confirm, are you using Column view? Follow the steps in this article: Read emails in Mail on Mac
"Change how emails are shown
In the Mail app on your Mac, do any of the following:
Try adjusting your Preview, for example does this occur using Side Preview?
Does this occur with every email? Or specific ones? does it happen constantly or is it intermittent?
See if the same thing occurs in safe mode and another user account:
How to use safe mode on your Mac
Set up users, guests, and groups on Mac
Cheers!
Thanks for getting back to us Saxman,
With Side Preview enabled, you should see your mailboxes in the left most portion of the window, a preview of your messages to the right of that, and when one is selected, the body of the message in the right most portion of the window.
If this isn't what you're seeing, and column layout is enabled, try disabling that option.
As far as the paperclip icon, this is simply letting you know that the message contains an attachment.
The Filter icon, filters a mailbox to show only unread messages.
The Mail User Guide offers additional information on the features of Mail and how to navigate the app: Mail User Guide
If you need further assistance, or aren't seeing what you expect, we recommend reaching out to an Apple technical expert: contact Apple Support
Cheers!
Thanks for providing the screenshot Saxman,
You can enable the side preview in Mail by clicking View > Show Side Preview.
The size of columns can be adjusted by dragging the dividing line. For example, drag the vertical line between your Mailboxes, and messages, or messages and Side Preview.
If these steps are not working for you, Apple Support will be the best place to get additional assistance.
Take care!
OK, I set it view Side Preview, and I see no way to see it on the side, I highlight a message, and there's nothing I see that would enable me to drag the side, nor does anything open on the side, etc. What's supposed to be happening?
Also, I noticed there are no longer any column lines, so how can I adjust the size of each column? And just noticed, since I couldn't find them before, that the little paper clip icon (denoting attachments) is now stuff all the way on the right hand side, which of course, makes no sense, nor could I find any way to move it. Finally, along the top, all the way to the right, is a tiny symbol that even when I put my cursor over it, doesn't say what it's for. Only when I clicked on it, did I see it says "Filtered by unread", as it did filter all the messages. Why no way to know what the thing does? And what does "Show tab bar" mean? What tabs are in Mail?
There used to be a line by line explanation of what each preference option means, in Apple Help, but no longer, so we're left on our own to try and figure out all the new options, and changes from what used to work fine, & ends up wasting lots of time, attempting to figure things out, and find answers from somewhere.
Nothing looks as it shows in the Mail Help, I turned off Show Column View, and it now has the List Preview for each email, which shows two lines, but that's it, no preview to the right side or below. so no way to see a preview whatsoever. The paperclip icon is now on the far left side (which makes more sense), however, it's jammed in a tiny, narrow column, along with the circle that shows if it's been read or not, and where any flag would also go! Why jam them all up in so tiny a space, when I've got all kinds of room? Plus, there's still no way to adjust the spacing of the display, so I can't make that column any wider, and the messages take up all the rest of the space. Why is there no preview?
You can see below, the picture in the Mail Help doesn't look anything at all like what I see, on the right.
I've done that, selected Show Side Preview, and there are no dividing lines, as I thought the screen image made clear. So I guess I'll have to try Apple Support, to see why this is, or isn't happening... thanks.
Mail Won't Show Previews...
