Today I needed to clean up an email account. After setting up the IMAP account in Outlook 2013, I proceeded to start trying to delete email. I was rewarded with this error message:
After some Googling and reading many 'microsoft bashing' posts, I stumbled on a useful comment.
To resolve this issue, open the advanced settings for the account in Outlook
FILE > Accounts Settings > Change > More Settings > Advanced (Tab)
In the ROOT FOLDER PATH, specify the folder 'inbox' (no quotes).
This resolved the issue for me and I'm happily deleting emails faster than an Enron exec.