Okay I seem to have resolved my problem, which makes me ask another question. It turns out that most of the Plugins were disabled. I enabled Java, which is what I think fixed the problem, and Microsoft Office 2013. So my next question is I have multiple Plugins and all but three of them are disabled. I think they got disabled with the update. How do I know which Plugins to enable?

I don't think you can do it automatically. Most add-ons are developed and maintained by individuals: some of them are very good at keeping their add-ons up-to-date as new versions of Thunderbird are released, others less so. You could try removing and reinstalling the disabled add-ons via the Add-ons Manager, but you'd have to do it one by one, and there's no guarantee that all will work with 45.

Plugins should all be disabled. They may be useful in a browser, but not in an email client. The Java plugin certainly isn't needed to retrieve mail..

Well it turns out Charter is having a problem. In talking with Charter I noticed that if I deleted an email from my Inbox it went into the Trash on Thunderbird.

I have Thunderbird configured to put it in the Trash Folder on Charter.net. When I brought up Charter.net I noticed that emails I had deleted with Thunderbird were still in the Inbox on their email application as well as in the Trash Folder.

When I deleted the email from the Inbox on the Charter application all of the emails that were deleted with Thunderbird disappeared. I did not realize that was the problem.

I did not test again until I had enabled add-ons and it was working, so my assumption were the add-ons.

I went to my wife's PC, she was having the same problem, I looked at add-ons and they were enabled. So I started l going back all my steps I had taken on my desktop.

When I checked the Charter application for her email I noticed they were in her Inbox. When I deleted them through the Charter application Thunderbird starting working correctly.

I called Charter back and they admitted that they had a problem deleting emails and had been having this for about two weeks, when interestingly enough this started.

So my suggestion to anyone having strange problems with Thunderbird and Charter is to check the Charter application. See if you see anything strange.

OP started a new quesion about deleting emails in charter not being deleted off server. However, it would appear the person is already aware of this issue and has confirmed it is acknowledged by charter. re:I called Charter back and they admitted that they had a problem deleting emails and had been having this for about two weeks, when interestingly enough this started. For anyone interested..... Link to other query: 'Why does a copy of email stays on server'

• https://support.mozilla.org/en-US/questions/1122086#answer-875862

I have the same issue as the original post. I cannot receive new email messages from Charter unless I close and relaunch the program. Several people also have this issue that I have talked to on other forums. This also happened immediately after upgrading to v45.0

I've re-installed old version of Thunderbird. I'm now running 31.8.0. I've deleted my email account from Thunderbird. I've tried both the mobile.charter.net and IMAP.charter.net settings they have on the website. Nothing works. I still can only get email if I shutdown and restart the program.

I've never installed a plugin Thunderbird. I have plugins installed on Firefox though. I see that Thunderbird lists the plugins that are installed on Firefox. I'll try messing with this.

Charter will not admit that they have a problem.

This is what I don't understand. You can have multiple emails that have been moved or deleted via Thunderbird and they still exist in the Charter.net Inbox as read. Then you can delete anyone of the moved or deleted emails from the Charter.net Inbox and all of the moved or deleted emails disappear. Charter.net must know the status has changed since it only deletes those that have been moved or deleted. Once the emails in question have been deleted Thunderbird starts receiving emails. So what really confuses me is how can any sane person think the problem is caused by Thunderbird.

By the way I think it started for me when I upgraded to v45.0, but I think that is about the time Charter made a change to Charter.net and they admitted that they were having problems deleting emails. They claim this has been resolved.

I understand that this points to a Charter issue. However, after 10 or more years of using Charter and Thunderbird with zero issues, it was one heck of a coincidence that it happened immediately after updating to Thunderbird v45.0.

I have still not solved this issue. I have disabled all plugins from Thunderbird. I have over 2,000 emails in my Inbox. I almost never delete email. However, I did delete an email recently. I cannot find this email on either Charter.net or Thunderbird.

I tried deleting another email. I did see that Charter.net had this email in Trash but it also had this email in the Inbox. I deleted the email from Charter.net inbox and purged the Trash. This did not fix my issue.

I am at a complete loss on what to do next.