In Thunderbird I have some email folders names that were changed and I also created new folders and I cannot see them after restarting Thunderbird how do I get these folders back?

Changed how?

I changed the folder names myself. When I have had this problem in the past, I went to my ISP's website and created new folders and copied all the emails in the folders I could not see in Thunderbird to the folders with the new names. This time, that tactic did not work 100%. There was a folder that I could not see at all, and I actually went to another empty folder, changed the name of this empty folder, and copied the emails from the folder I could not see in Thunderbird to this folder where I had changed the name. I then saw that I needed to update Thunderbird to a newer version. When I did that, I saw some of my missing email folders, but not the folder that was previously empty, where I changed the name of that folder and moved emails to this newly named folder. I hope you can help me with this.