Changed Thunderbird from POP to IMAP

Do not delete your POP account until you are sure. To get your lost emails, you need

1. restore your POP profile if you still have it https://support.mozilla.org/en-US/kb/profiles-where-thunderbird-stores-user-data#w_backing-up-a-profile

or 2. You have set "Leave messages on server" for your POP account, then you should still have the emails on your server.

I created a user profile for IMAP and all was OK....Until I deleted the profile for POP and I lost all e-mail folders that I didn't move to IMAP.

Did you really create two Thunderbird profiles, one profile with the POP account and then a second profile with the IMAP account? Or did you have one profile with the POP account and then set up an IMAP account for the same email address, in order to copy messages from the POP to the IMAP account? Normally, when you delete a POP account in Account Settings, Thunderbird prompts to remove only account information but not the message data. We don't know whether you checked "Remove message data" and probably you don't remember.

To verify if your message data are still stored in your Thunderbird profile go to >> Help > Troubleshooting Information > Profile Folder > Open Folder: in the profile folder go to Mail and verify its contents. Does it contain an account folder something like "pop.xxx.xx" and does this folder contain mailbox files such as Inbox, Sent, Drafts, Archives, Trash?