[IMAP] Unable to create trash folder on server (Invalid mailbox name)

I’m a new eM user moving from Outlook. I imported mail ok from my old pst file. Generally I like the application. But I have a problem when deleting mail. The Trash folder remains empty and it has a red “!” next to it. I also get this error message:

[IMAP] Unable to create folder “mailbox/Trash/” on the server. (Invalid mailbox name.)

n.b. it shows my email address for mailbox above,.

As I am able to send and receive e-mails without error, how can the mailbox name be invalid?

Please note I have read the posts about duplicate Trash folders on servers, but in my case I have never used IMAP before. I used to use POP3 with Outlook. So there shouldn’t be an existing Trash folder on the server. The mail server is on my own domain, and is hosted by my ISP.

Thanks, John


If you are using IMAP and do not store any emails locally, I recommend deleting and re-adding your mail account. What probably happened is that during the import, the Trash file somehow got converted into a locally created Trash file, which the server doesn’t recognize and does not allow. When you recreate your account, it will sync with the server’s Trash folder and should work properly.


Hi Dave, I’m in a similar position.
Whenever I sent, delete or save an email, a new trash/sent/drafts folder is created and I get the following error:
[IMAP] Unable to create folder “mailbox/Trash/” on the server. (Invalid mailbox name.)

I can find no way to alter the server location for these folders and simply want items to be placed in the existing folder already on the server. Previous posts make reference to Default folders - I have no obvious option to alter where sent/drafts/deleted items go. Altering Automatically detect special folder names also has no effect. Please help

Hello Daniel,
can you please copy the full content of the Tools>Operations>Log window next time this error appears?


I resolved this and forgot to update this post -sorry"!
The problem was caused by the way iMAP is supported by my ISP. I was previously using POP3 mail in Outlook where the “Deleted” folder is not under Inbox.But when I moved to EM-Client and setup IMAP I did not realise then, that my ISP stores all folders under the Inbox folder, including the Trash folder. I gather this is for historical support reasons. 

Here is how I got around the problem:

  • Go into Tools\Accounts.
  • select the IMAP tab
  • Scroll down to the “Special Folders” section.
  • You will see text boxes for entering folder paths.

These were empty originally. I populated them with the following relative folder paths, and doing so cured my problem after restarting EM-Client:

Sent box:    Inbox.Sent
Drafts box:  Inbox.Drafts
Trash box:  Inbox.Trash
Junk box:   Inbox.Junk E-mail

The paths may be different for other ISPs, so in the event the above don’t work for anyone reading this, check the required paths in your ISP’s support documentation.

n.b. I leave un-ticked the checkbox “Automatically detect special folder names”, as automatic detection doesn’t always work.

Hello John,
thank you for sharing your solution on the forum.


Thanks John, That worked well enough. I no longer get errors but a new sent/trash/deleted etc was still created, leaving me with my old folders and new. I bit messy but seems to work. Certainly I haven’t able to retain use of my old sent/deleted/junk emails which would have been nice. Thanks

Hello Daniel,
you can set your old folders as the Special folders.
Instead of the ‘Inbox.Sent’ etc. use the actual server locations of your folder.
Right-click and look at properties to see the folder location of your desired folder.


Ok thanks, that’s just about working. Still having problemds with trash/deleted items but I’m done messing around with that


Ive followed the above but still continue to get these messages. Ive deleted my account, recreated and set my special folders to inbox.* and still get the same problems. Any other ideas to resolve this?


I am getting fed up with this there is nothing intuitive at all about what is happening unable to create folders every time I open it invalid mailbox name then self disconnecting requiring a restart it downloads my mail but I have zero confidence if its current or old can some body sort it or do I have to ditch another email client how I long for the ease of outlook.
Sorry Win 10 none of the above works well not for me