Item one,. If you want a backup of the gmail mail, use the Gmail takeout service. Thunderbird is not really meant to the purpose you are using it for and that may well be why you are having issues.

Thunderbird connects to each POP account every 15 minutes by default. It could be that between that and your antivirus product slowing things down that only a few email arrive before the download crashes and it has to wait another 15 minutes.

Note local copies of IMAP mail account can be considered nothing more than a local cache and mail in those account will be deleted it the server copy is not available so it is a terrible choice as a backup of anything.

Firstly, It makes no difference whether I download mail every week or every day, the behaviour is the same. I click on the "Get ALL NEW mail" button it only downloads 15 emails. If I click the button immediately again it downloads the next 15 emails and so on until all new emails are downloaded. Secondly, I do not see any error messages to say the email download has failed for any reason. Thirdly, clearly the "Get ALL NEW mail" button is not NOT downloading ALL NEW mail, it is downloading a subset of the available NEW emails, or should the button be renamed "Get partial new mail" Just a thought, maybe you could advise on something I could do to narrow down what the actual problem is?

I have come across this sort of complaint in the past and it was gmail POP account.

It seems that gmail deliberately cause this nuisance when users have a Pop account to download mail, but they have the setting to Leave messages on the server. When server starts to get a lot of emails using up quota, gmail suddenly will only do limited downloads and it only gets worse as time progresses. It's almost as if gmail wants you to get annoyed, believe Thunderbird is a pain and logon to their webmail and use it instead.

In all of the cases, I advised to do the following and in all those cases it worked. So it's worth trying to see if this was the cause of your issue.

Logon to the gmail webmail account via a browser and delete a load of old mail. Pop accounts cannot put deleted mail into the server Trash folder, so gmail ends up with archiving old mail in the 'All Mail' folder. You can tell what is archived because the emails in 'All Mail' will not have any 'labels'. You need to delete emails from the 'All Mail' account that do not have any labels or if you have a load of emails in Inbox - delete them so they go into the gmail Trash and then you can empty the Trash. Basically get rid of your old emails of server. Pop account will have a copy of all emails because Pop account folders are independent of server.

In Thunderbird Make sure you have compacted Inbox folder to ensure all old traces of 'marked as deleted' mail are properly removed.

Many thanks for your constructive and detailed reply, I will try your suggestions at weekend and report back.

If clearing cache and disabling extensions didn’t help, try starting Firefox in **Troubleshoot Mode** (Help > Troubleshoot Mode). This disables all add-ons and uses default settings, which can help identify if an extension or theme is causing the issue.

Also, ensure that your **graphics drivers are up to date**, and check Firefox’s **Hardware Acceleration** settings under *Settings > General > Performance*. Try disabling it and see if the issue persists.

Let me know if the problem continues after these steps!

I have come across this sort of complaint in the past and it was gmail POP account. It seems that gmail deliberately cause this nuisance when users have a Pop account to download mail, but they have the setting to Leave messages on the server. When server starts to get a lot of emails using up quota, gmail suddenly will only do limited downloads and it only gets worse as time progresses. It's almost as if gmail wants you to get annoyed, believe Thunderbird is a pain and logon to their webmail and use it instead. In all of the cases, I advised to do the following and in all those cases it worked. So it's worth trying to see if this was the cause of your issue. Logon to the gmail webmail account via a browser and delete a load of old mail. Pop accounts cannot put deleted mail into the server Trash folder, so gmail ends up with archiving old mail in the 'All Mail' folder. You can tell what is archived because the emails in 'All Mail' will not have any 'labels'. You need to delete emails from the 'All Mail' account that do not have any labels or if you have a load of emails in Inbox - delete them so they go into the gmail Trash and then you can empty the Trash. Basically get rid of your old emails of server. Pop account will have a copy of all emails because Pop account folders are independent of server. In Thunderbird Make sure you have compacted Inbox folder to ensure all old traces of 'marked as deleted' mail are properly removed.

Thanks so much, this worked perfectly. I didn't know that Google throttled email downloads if I'm running low on space. Thanks again for the constructive answer. Others on here could learn from you.