Gmail is known for deliberately blocking downloads. This tends to occur if the user is using a POP account or an Imap account that does not use OAuth2 as the Authentication Method. They claim it is for your safety.

Logon to gmail webmail account and check the 'Less secure apps' option. Gmail may have switched it off, so you have to select it again. It basically forces you to logon to their webmail access.

See info : https://support.google.com/accounts/answer/6010255?hl=en

Whilst you are logged on to the gmail webmail account, it would be worth checking the contents of your 'All Mail' folder. Pop accounts - assuming you keep copies of messages on the server when you download - can only remove labels when you delete an email, thus archiving all your deleted mail in the 'All Mail' folder. Recommend you go through the 'All Mail' folder and delete any old emails that you know you have deleted. This will gain you more quota space on the server.

"Toad Hall",

Thank you very much for your reply, which reminded me of this Google behavior. I had run across it several years ago during a trip in Europe when Firefox stopped working and the problem proved to be that Google considered it an insecure device. Fixed that by setting Google to accept insecure devices.

With that thought in mind, I checked to see whether Firefox (not my usual browser these days) was still working. YES. Well, that didn't prove that Thunderbird hadn't been tarred with the insecure-apps brush. So following your suggestion I checked to see whether "less secure apps" were still permitted on my POP account. Again YES. Hmmm, what could be the problem?

Eventually I decided that perhaps Gmail didn't approve of the e-mail at the bottom of the string that hadn't downloaded. So I moved only that message (which contained an attachment I didn't and haven't opened) to the server's spam folder. Thunderbird "get messages" then started and proceeded as if there had never been a problem.

But it didn't download all 70+ messages, only the first 50 or so. So again I moved the bottom-of-the-list message to the Spam folder (this was innocent-looking text from a known regular correspondent), and again the message download started and this time ran to completion as if nothing had happened.

I can only conclude that some unexplained and unflagged content in these two messages caused Gmail to call a halt. There's no marking on the server content to make the cause obvious, no blinking red text etc. So I don't understand what could have happened. It puts me in mind of a problem probably all of us have seen on occasion, a seemingly innocuous string of typed characters causing an app to do something unexpected.

So although your original suggestion didn't solve my problem, it reminded me of something to check and then when that proved a dead end, spurred me to try a different tack. And THANK YOU for that! I would however like to know what Gmail saw that it disliked sufficiently to halt further downloads.

And thanks for your email handle, which reminded me of The Wind in the Willows which I haven't thought about in many years. And Mr Toad's wild ride!

Martt Harding

That would have my next suggestion :) If gmail had not switched off less secure apps, then you have what is generally known as a log jam - an email blocking downloads. Good to hear all is working again.

For Toad-Hall,

Well, I'd like to say all is well. But it isn't. I thought, incorrectly as it turned out, that a log-jam problem was the cause. The symptoms seem to evolve, or more likely I don't recognize what is going on. I think I have reset all logical Gmail settings without fixing the problem.

At present I have perhaps 15 unread/un-downloaded e-mails on the Gmail server. Thunderbird's "get mail" function detects it, shows a different count of unread messages to download, but doesn't download them. I've tried the trick that worked before, moving the earliest unread message to Spam so the rest could download. Doesn't work any longer.

I'm beginning to wonder whether something is wrong in Thunderbird. I'm using 32-bit 78.14.0 and was thinking about reverting to a much earlier version e.g. 68.x.x but evidently there were some significant changes when going to version 78 so reversion may not be a viable option. I'm concerned about my hundreds of file folders of message traffic in the profile folder getting zapped. Or the address book. So far I haven't found any evidence of a "repair" capability in Thunderbird, to essentially download a fresh copy on top of the current one. Perhaps there's a non-obvious function equivalent to Windows 10's System File Checker?

And now Thunderbird is recommending an update to 91.1.1. Which doesn't seem a good idea, could simply make everything worse.

I've considered deleting my account on Gmail and starting over but I think that would wipe out my email address and I don't want to go through that. And it wouldn't change the underlying Gmail code, if that's the problem.

One thing that's a puzzle is that as a result of this thrash I've realized that both POP and IMAP are enabled on the server. I don't remember doing that, don't think I did, since I've never used IMAP and anyhow I thought the two approaches were mutually incompatible. I don't think this a problem for me since I use only one device, this laptop using POP, to download and archive my email. I haven't tried disabling IMAP on the server (yet).

Any suggestions would be gratefully received and tried. This is proving remarkably frustrating.

Martt Harding marttharding@gmail.com

I doubt the issue is with Thunderbird.

In webmail did you empty the Spam and Trash folders? Have you got rid of all the old or deleted mail in 'All Mail' folder? Basically given gmail webmail account a clean up.

re :. I'm concerned about my hundreds of file folders of message traffic in the profile folder getting zapped. Or the address book.

Perform a backup - I do it manually as it so easy.

If you are currently using eg: 78.14.0 On external drive create a folder called 'TB Backup-78-14-0' ready to receive the backup copy.

In Thunderbird

• Menu app icon > Help > Troubleshooting Information
• Under 'Application Basics' about 11th in list is 'Profile Folder' - click on 'Open Folder' - see image below

A new window opens showing the contents of your 'profile name' folder

• Exit Thunderbird now - this is important

• Go up directory 3 levels to the 'Roaming' folder - see image below
• Copy the 'Thunderbird' folder and paste it into the 'TB Backup-78-14-0' folder.

Usually most cases to do with a simple pop account tend to be at the gmail end. Either gmail blocking for some reason, eg: less secure apps, email log jam, folders needs clearing down, quota's reached so cannot even receive an email until emails are deleted or limits on bandwidth usage have been reached etc.

Thunderbird - the program - is usually is not at fault. But something within the profile maybe causing the issue.

In Thunderbird there are a couple of things you could check out. The Inbox index file could be squiffy, so you could rebuild it.

• Right click on 'Inbox' and select 'Properties'
• Click on 'Repair Folder' button
• click on 'OK'

In Thunderbird profile, one folder that could be causing an issue is the 'popstate.dat' file.

The 'popstate.dat' file keeps a record of what has been downloaded, so that the next time the server Inbox is accessed, Thunderbird knows what was downloaded previously otherwise it would dowload everything in the Inbox each time.

It is perfectly ok to delete the 'popstate.dat' file if you suspect corruption. A new one would be created when you restart Thunderbird. The only draw back is everything in the server Inbox folder will get downloaded. So to get around that you would need to access gmail webmail first and move everything already previously downloaded out of the 'Inbox' and either delete it or create another folder called eg: 'Store' to hold all those 'Inbox' emails.

Then do the following to delete and create a new popstate.dat file in Thunderbird gmail pop account.

• Menu app icon > Help > Troubleshooting Information
• Under 'Application Basics' about 11th in list is 'Profile Folder' - click on 'Open Folder'

A new window opens showing the contents of your 'profile name' folder

• Exit Thunderbird now - this is important

• Click on the 'Mail' folder
• click on the pop gmail account name folder
• locate and delete the 'popstate.dat' file

Start Thunderbird The new 'popstate.dat' file gets created and anything you left in the server Inbox should get downloaded.