WThe IMAP command “UID COPY” (to Trash) failed for the mailbox “INBOX” with server error: UID COPY Command is not valid in this state

Seen several reports on this including myself. Seems to be a problem with Yahoo accounts. Who is your provider?

To get mine working, I went to accounts in preferences and disabled the account, then re enabled it. This happened several times to me yesterday.

Yahoo! finally took some of the blame for this, but Mail in High Sierra is a bit culpable as well.

In particular, Yahoo's IMAP servers can respond to an IMAP "CLOSE" command sent by Mail with the response:

    NO [SERVERBUG] CLOSE Server error - Please try again later

Unfortunately, that response to that command is illegal according to RFC 3501 - INTERNET MESSAGE ACCESS PROTOCOL - VERSION 4rev1. The CLOSE command is only allowed to return "OK" or "BAD," not "NO."

The High Sierra portion of the failure is that after that, Yahoo!'s IMAP server sends the response:

    BAD [CLIENTBUG] CLOSE Command is not valid in this state

to any future commands Mail sends until the response finally is seen as a command failure to Mail, which generates the error dialog box.

Instead, Apple Mail really needs to detect the error immediately (i.e. it needs to detect when an IMAP server has returned an illegalresponse to a command) and then needs to either report the failure or forcibly close and reopen the connection.

A workaround is to tell Mail to store Trash in the folder "On My Mac" rather than use the Trash folder on Yahoo!'s servers.

Wait a while and you should be able to delete messages. If not, open Mail preferences and disable the account. Restart Mail and re enable the account.

Also, might be time to leave feedback. It seems to be a problem with Yahoo accounts.

Feedback - Mail - Apple

The temporary solution is using Option + Delete to permanently delete emails without Trash bin.

Hope Yahoo and Apple will fix the issue soon.

Yahoo! has acknowledged the bug and is working on a fix they plan to release by the end of this week.

Yahoo! has acknowledged the bug and is working on a fix they plan to release by the end of this week.

Yahoo! has acknowledged the bug and is working on a fix they plan to release by the end of this week.

Same here. It's a High Sierra/Yahoo Mail problem. I have a Mac Pro running El Capitan and an iPad running iOS 11 and can delete mail with no problem. My iMac 5k is running High Sierra and that's where the problem is.

It just happened again. I was unable to delete a Yahoo/ATT message, but had no problems deleting an iCloud message. After a minute, I was able to delete the Yahoo/ATT message without doing anything else.

Earlier today, Apple released macOS High Sierra 10.13 Supplemental Update, which has a specific fix for the Yahoo! Mail issue.

It should appear automatically in your App Store Updates tab, or download it directly:

macOS 10.13 Supplemental

gottapulse wrote:

Interestingly my Mail app is now deleting successfully even though I have yet to receive the supplemental update. Thank goodness a fix has now been created.

Same here. I didn't install the Supplemental Update yet.

Well remember there are two parts to the bug, one at Yahoo! and one with Apple Mail.

It could be that both halves of the issue are now fixed. 😎

Post back with the results. I can't determine if this is only with Yahoo. It hasn't happened with iCloud mail. The occurrence is several times a day and not sure why it's happening. Sometimes, you just have to wait a while for it to clear up.

I don't know what's causing it, but connection doctor shows all connections are good when it does fail.

Same here. Just upgraded to High Sierra. Email is @att.net. Deleted and re-added att account multiple times, problem still persists.

The IMAP command “UID COPY” (to Trash) failed for the mailbox “INBOX” with server error: UID COPY Command is not valid in this state.