re :I went through endless attempts to correct that using information on this web site and other sites on the Internet. None of those propose solutions work.

It would help if you said what you did.

Did you start computer in 'Safe mode with networking' and then start Thunderbird as normal? If not then test this and report back on results.

Did you uninstall Thunderbird via Control Panel > Programs and Features. Then Start Computer in 'Safe mode with networking' and then download and install a fresh version of Thunderbird for your OS from here: https://www.thunderbird.net/en-US/thunderbird/all/

It is possible that your Firewall is blocking Thunderbird because it does not realse the update is the same program. You would need to make sure Thunderbird was not running in the background, access Firewall which may be part of your Anti-Virus program. Block Thunderbird, ok it, then Access Firewall again and set Thunderbird to be allowed. Do not simply disable Firewall.

What AV product are you using?

Did you try uninstalling 60.3.0 and installing a previous version to see if you could get everything working again: http://ftp.mozilla.org/pub/thunderbird/releases/52.9.1/win32/ choose prefered language then download and run the installation file.

Thank you for getting back to me right away, Todd. Sorry, I didn't keep detailed notes of all the steps I attempted to resurrect my Thunderbird 60.3.1. One of things on numerous websites is to go in and delete the parent.lock file. I did this numerous times but probably as everyone knows as soon as Thunderbird is restarted, it puts parent.lock right back where it was so there's nothing gained. And there's nothing changed, performance wise. I also tried reinstalling Thunderbird 60.3.1. I did go through the procedure of totally deleting Thunderbird via Control Panel > Programs and Features. Then Started the Computer and installed a fresh copy of hunderbird from the Mozill a website.

After I wrote to you last night, I tried one last thing. I changed the file name on the Thunderbird profile folder in AppData/Roaming and restarted Thunderbird. Thunderbird started up normally and I was able to recreate my e-mail accounts from scratch. So 60.3.1 works. It just doesn't seem to like my profile. I have not been storing e-mail messages on the various servers so I have no way to access old saved messages except by regaining use of my former profile.

I'll try installing the previous version (52.9.1) to see if I can get everything working again. I take it I should uncheck the maintenance feature.

Todd, I was able to download version 52.9.1. After a couple of runs at this I was able to find the configuration setting to turn off the automatic updates deep within tools /options /advanced, and everything is working the way I wanted it to. My original Thunderbird profile is functional.

Prior to finding that configuration setting, 52.9.1 did automatically update to 60.3.1 and I was back in trouble. The system was running, according to Task Manager, but there was nothing on the screen. Keep in mind this happened on two different machines with two different versions of Windows 10, but with the same TB profile. And by the way, both machines are running Windows Defender Malware protection (AV as you called it) which automatically updated.

I would like to keep up to date with TB, so please solve this problem

re :After I wrote to you last night, I tried one last thing. I changed the file name on the Thunderbird profile folder in AppData/Roaming and restarted Thunderbird. Thunderbird started up normally and I was able to recreate my e-mail accounts from scratch. So 60.3.1 works. It just doesn't seem to like my profile. I have not been storing e-mail messages on the various servers so I have no way to access old saved messages except by regaining use of my former profile.

There is an addon called ImportExportTools which can be used to import mbox files (they have no extension) from one profile into the current profile. https://addons.thunderbird.net/en-US/thunderbird/addon/importexporttools/

Download xpi file. Install into Thunderbird via Menu icon > addons > extensions Restart Thunderbird Right click on mail account name or a folder to see ImportExportTools as an option. See images as a guide.

Todd, thank you again for information provided back in November when I first started having trouble with Thunderbird not appearing on the screen, but appearing in Task Manager as an active application. Since then I've been getting along with the old version. However, there's further information that I think Mozille needs to know.

In addition to my PC where I do most of my e-mail work, I have a laptop with the same Thunderbird version and same e-mail accounts. The point here is that the laptop started having the exact same problem. So this is a systemic problem with the software starting with version 60.3.1.

The other important thing is that I am now operating both machines with the latest version (60.5.0) of Thunderbird and most of my profile after experimenting with disabling various parts of the profile. The result it that I have disabled my address book on both machines. When I enable that original address book, the problem reoccurs. When I disable the original address book Thunderbird works normally. Because they were dated 11/26/18, I've also disabled origional versions of

• addonStartup.json.lz4
• cert9.db
• zkey4.db

These seemed to be causing problems too.

Of course, with clean reinstallations, Thunderbird replaced these files. Thunderbird also created a new address book. Since I have my e-mail messages, a new Collected Address Book was created. So, although I lost my personal address book and all of my distribution lists, I have most of the addresses captured and can recreate distribution lists from those.

If anybody would like to look at the files I have disabled, I'll be happy to forward them.