Mail App: Organizing Mailnbox Subfolders

Boot into Safe Mode (Use Safe Mode to isolate issues with your Mac and Playing Safe: what does Safe Mode Do?) and try to reset the folder organization from there.   Reboot normally and test again.

NOTE: Safe Mode boot can take up to 10 minutes as it's doing some system cache cleaning, volume verifying and directory repairing. 

You should be able to. You should get an insertion like that pops up when you drag.

Another person posted the same problem. I'm not sure if I am seeing anything different, but I don't have a problem rearranging them. I am running 10.15.4, but I don't know if that makes a difference.

Same problem, but when you get the "placement bar" or whatever you call it, Mail only allows me to arrange within that level, I cannot go "up" a level. Is there some sort of vulcan neck pinch keystroke combination required to do this very simple task. People make mistakes, Apple should accommodate.

No joy. Perhaps another piece of information might be helpful. It is an exchange account. However if I moved it once, and the change was reflected on my phone it shouldn't make a difference. I promise I won't touch the folders again, and live with them out of order!

The only other thing I can add is you move the folder icon such that the insertion bar goes where you want, not the folder. Notice in my screen shot that the folder is way to the left to get the bar where it needs to be.

Solved it! Tongue and Cheek, but I really did fix it. Go download outlook, install your credentials and then move the folder back up a level. Then it is corrected in mail. Delete Outlook if you want afterwards.

C'mon Apple!

You could have just logged into your email provider's web portal and done the same thing.

As I stated, Apple Mail does not support subfolders of the Inbox.

Mail doesn’t really support sub folders of the Inbox. It’ll show them if you have them, but everything else is flakey.

I have no idea. I imagine they do not expect anyone to create subfolders of the inbox, so didn't spend any time making that possible.