1st Apr, 2014 by Cam
If you can't delete IMAP email messages on your iPhone, and are getting the message "Unable to move messages to trash", chances are you need to set the INBOX path prefix.
What does that mean?
The problem is that most mail servers use a folder to store new messages in. This folder is appropriately named 'INBOX'. The generally accepted standard is that new mail should be stored in the 'root' (i.e. the top, or ) folder, rather than the subfolder called 'INBOX', but that is not what most mail servers do.
This is very easy problem to fix. I'm not really sure why the iPhone Mail app doesn't set it's self up with the common settings by default (I'm pretty sure it used to). It does make some sense to default to the official standard, rather than give in to the less-than-perfect status quo.
How do I fix it?
Luckily you can fix this issue in a few quick steps. Just follow the instructions below, and you should have your mail performing as it should in no time at all.
Open 'Settings' on your iPhone, and navigate to 'Mail, Contacts, Calendars'
Click on the account you want to fix
Click on the area below the word 'IMAP' that says 'Account' followed by the email address we are fixing.
Scroll down to the bottom, and click 'Advanced'.
Scroll down to the bottom to where it says 'IMAP Path Prefix', tap the field, and enter the word INBOX in capitals.
Click '< Account' at the top left of the screen, and then 'Done' on the top right of the next screen.
That's it! Your mail account should now work as it should. Repeat the steps for any other mail accounts you have that are having the same problem.
If you have any feedback or questions, just let me know in the comments section below.