There are several ways to avoid unwanted updating of IMAP folders:
- Never look in the folder and Mail.app will not try to update the contents (according to my observation - may not actually be true).
- If you have looked in the folder, navigate to the ~/Library/Mail directory and delete the corresponding .imapmbox file and/or the sub-folder containing additional .imapbox files.
- Create a link to /dev/null in place of the folder you want to ignore. For example, say there is an IMAP folder called "WorkOrders" you don't want to read, do the following:
Even if you click on the "WorkOrder" IMAP folder, Mail.app does not attempt to read the messages so there is no delay. If you ever decide to want to see the contents of the folder again, simply delete the link and Mail.app will update the contents when you next open the folder.ln -s /dev/null ~/Library/Mail/WorkOrders

