(no sender) junk mail won't erase from folder
I have tried multiple ways to remove/erase the (no sender) junk mails from my junk mail and they just sit there.
Safe Boot from the HD, (holding Shift key down at startup), does the problem occur in Safe Mode?
Safe mode attempts to repair Disks & clears lots of caches, so if Safe Mode works try again in regular boot.
Quit Mail & login to your WebMail in a Browser, if possible delete any them there.
Start Mail...
If you have no POP accounts & they’re all IMAP accounts then in Mail’s Mailbox menu choose Rebuild.