I have been using POP for many years with multiple devices (Win XP workstation, iPad, iPhone). I recently ran into a bit of a problem with a new Win 10 laptop that was set up as IMAP. The result was multiple copies of emails on all of the devices. I have shut down Outlook on the new laptop until I can figure this out.
After some research, I realize that I need to decide whether to use POP or IMAP and set all of the devices the same. I think it is time for me to convert everything to IMAP, but before I do, there are a couple of details about how the email folders are synced that I do not understand.
In the Outlook Mail panel, I see a list of folders. The top level folder is named “Personal Folders (Unicode)”. There are 9-10 subfolders: Deleted Items, Drafts, Inbox, Inbox2, Junk E-mail, Messages, Outbox, RSS Feeds, & Sent Items. Some seem hardwired and some I created. Many of them have sub-subfolders.
I have more than one email account. They do not all come from the same ISP.
If I convert everything to IMAP, will all of those folders and subfolders get synced? That is, will all of those folders suddenly appear on all of the devices including the iPad and iPhone?
Yes and no.
It can depend on the email client and/or device.
Folders will appear available on all devices. Whether or not the contents of those folders will automatically download to that specific device will depend on the device and/or email client.
For iOS devices, all the folders are synced, but not everything is downloaded automatically. Generally, only new and relatively current messages are downloaded to the Inbox. Most other folders will not download unless you view that folder. Anything that you do change in a folder (i.e. delete a message or flag a message [for most IMAP systems]) will be synced back to the IMAP server, whether in a folder that automatically downloads or only does when you visit the folder. It is done this way so that you don't hog a lot of space on your iOS device with old email messages that you likely don't look at hardly at all. In other words, the assumption is you don't want to take up a lot of space with email messages on a device that might have limited storage space.
For Apple Mail on my Mac, it will automatically sync all sync and download all folders. Here is it assume that I have much more storage space, which I do.
It has been a long time since I used Outlook on Windows, so I don't really recall the specifics. But, if memory serves me correctly, you can have it behave either like Apple Mail does on my Mac, but I also believe you can de-select certain folders to automatically sync. I could be wrong on the later part.
Is there a way for me to create an email folder that will not get synced? That is, is there a way for me to move an email on one device to a non-synced folder so that it will appear to the other devices that it was deleted and so get delete everywhere else? And is this a bad idea?
Again, it will depend on the email client and/or device.
I am not aware of any way to do this on an iOS device with the Apple Mail client. About the only possibility is if you also have a POP email account setup in Apple Mail on an iOS device. In that case, you might be able to create a local folder that is part of the POP email account that will not sync with the POP server due to a POP email account's nature (POP email accounts don't sync). It is possible that other email clients (such as maybe Outlook) could allow local folders outside of an IMAP account without also having a POP email account.
For Apple Mail on a Mac (and Outlook in Windows if memory serves...again, it has been awhile since I used Outlook), you can setup local folders that are NOT tied to any account. These folders will NOT sync. When you move a message from an IMAP folder to one of the local folders, this will then have the effect of deleting the message from the IMAP account. The message will then only be stored locally in that local folder (the message may still be in the IMAP Trash folder for a bit depending on how things are setup).
How does it work with two different ISPs (GoDaddy and Netgate)? With my current POP system, the emails from both ISPs go into the same set of folders. If they are all IMAP, will the entire folder structure from both ISPs get replicated on both servers?
Outlook will have two different PST files for each IMAP account (this I do remember) and each IMAP account is completely separate...i.e. will have its own Inbox, Drafts, Outbox, Trash and other user made folders, etc. Since POP accounts are not really "online" accounts, they all get lumped into one PST file that has one Inbox (which is a only local folder).
It will be very similar for Apple Mail on an iOS device in that all IMAP accounts are independent. I forget how multiple POP accounts are handled as it has been at least a couple years since I used a POP account now that Comcast supports IMAP, let alone multiple ones. I want to say POP accounts were still kept separate, but not 100% sure.
I believe Apple Mail on a Mac works basically the same as Outlook on Windows...i.e. stores IMAP accounts separately on the drive and definitely has separate folder structures for each email account. It also has the ability to all Inboxes together (as does Apple Mail in iOS) in addition to view each Inbox for each account. I forget if Outlook on Windows has this option or not.
So, generally speaking IMAP accounts are separate and will not "intermingle" on your devices or the servers. The only way a message from one IMAP account ends up in the folder (on the device and server) of another IMAP account is if you move that message there yourself.
Beyond your questions, the important thing to keep in mind is that what you do on one device will effect the other devices that connect to that same IMAP account. You may already understand this, but just in case you do not. So, if you delete a message from the Inbox on one device, it will be gone all all other devices (once that "deletion" propagates through whole system...i.e. up to the server and then down to the other devices...generally pretty instantaneous). If you read a message on one device, it will be shown as read on all devices. And so on. This is vastly different from POP.