If they are appearing, you are opening them... I have never heard of a single case since V3 was released with tabs of them opening by themselves.

You might try deleting the session.json file from your profile folder with Thunderbird closed as that is where tabs are stored, just in case the file is corrupt. But that is all I have.

No, I am definitely NOT opening them. Two days ago, there were 6 unwanted tabs open, one dated from Sept 2019, 3 different ones from Dec 2019, one from Xmas Day this Year, and one from 27th Dec this year. There is no rhyme or reason, 4 were from the Sent Box and 2 from the In Box. They are opening up themselves.

When I look at the Thunderbird profile, there is one file called imtei0st.default. Is this what I should delete?

Is this a possible reason? I have used quite a lot more than my allocated allowance in my ISP mail box. I am going through the emails, frantically deleting. Would this cause problems in Thunderbird?

Thanks for replying Win

re :When I look at the Thunderbird profile, there is one file called imtei0st.default. Is this what I should delete?

No. That is your 'profile name' folder. Do not delete it or you will lose everything.

But in that imtei0st.default folder you will see the 'session.json' file.

Close all unwanted tabs that are open. Now Exit Thunderbird then delete the 'session.json' file finally restart Thunderbird.

Thanks... I deleted the json file and restarted Thunderbird but I am still having the problem. This is the day after, I have had Thunderbird open for 30 minutes and currently have 2 unwanted tabs open, both from today, but I read both in the message pane and deleted them, definitely DIDN'T open them in tabs. This is so puzzling... and very annoying. Win

You completely removed any stored information by deleting the session file, so when you started up Thunderbird it had no knowledge about what tabs had been previously opened. The two emails that opened in a tab, were emails that had been selected to be viewed, even if you desired to see them in the 'Message Pane'. This tells us that this is not due to a session file gone awol, but occured within current session in a new session.json file.

When you click or double click etc on the mouse, the computer receives the information from the mouse and then performs the required acton that matches the event trigger in whatever program is running. So one possibility is that the mouse is sensitive to your touch and has passed on the instruction to computer of a double click. When the email opened in a tab, did Thunderbird immediately offer focus on that opened email in a tab?

As you are performing a lot of deleting, have you been compacting your folders to clean up the files and remove all marked as deleted and hidden emails? If no, then perform compact on those folders which have had a lot of deleting/moving of emails - right click on folder and select 'compact'.

What addons have you got installed - whether they are enabled or not?

I do not actually SEE the tabs open, so no, Thunderbird doesn't offer focus to the newly opened tab. I am only doing a lot of deletions in the Sent folder, yet the unwanted tabs are opening from other folders as well... In Box, and any of the several sub folders I have for mail from groups to be forwarded to. I haven't been doing many deletions in any of those, just the normal delete after reading a message in the message pane. No, I don't have any add-ons. I empty the Trash regularly, and I have just compacted the Sent Folder. I'll try doing this on a regular basis to see if it makes any difference. I don't agree that it may be a mouse sensitivity, because more than 90% of the emails that are opening in tabs have NOT been clicked on at all. I'll report back again in about 24 hours. Thanks Win

No need to wait 24 hours... for the last 30 minutes, I have been working in Photoshop, not using Thunderbird at all, it is just sitting open but minimised. I have not been doing any deletions for about 10 hours, and I have compacted the Sent box where I HAD been deleting earlier this afternoon ( 12.18 am here)

I just now went back to it to see if any new emails had arrived, and I have 7 unwanted tabs open, from 8th Dec, 15th Dec, 16th Dec, 22nd Dec, 25th Dec, 30th Dec and 4th Jan.

This proves that it isn't a problem with the mouse, I haven't been reading these emails, they are just opening up themselves even when the program is not being used!! Win

There really must be something being stored somewhere which was called when you maximised Thunderbird. So, the following is bit of a big cache etc clear out.

• Menu app icon > Help > Troubleshooting Information
• Under 'Application Basics' section - about 8th in list 'Profile Folder' - click on 'Open Folder'

A new window opens showing contents of 'profile name' folder. Leave window open as you will need it in a minute.

Back in Thunderbird.

• Close all unwanted tabs that are open.

• Menu app icon > Options
• Select 'General'
• scroll to 'Network & Disk Space' section
• Under 'Disk Space' - your cache is using....click on 'Clear Now'

• Now Exit Thunderbird - this is important

In the 'profile name' window which you opened earlier.... Locate and delete the following 3 files:

• panacea.dat
• session.json
• xulstore.json

Start Thunderbird.

When I started Thunderbird tonight, after about 20 minutes , 2 unwanted tabs opened one after the other. I have done the steps listed exactly as per instructions and definitely closed Thunderbird. However when I attempted to delete the 3 files in the profile name window, I got a message that it couldn't delete panacea.dat as Thunderbird was still using it and did I want to close Thunderbird... Thunderbird WAS closed, but I checked "close Thunderbird" anyway, then the files deleted successfully. I re-opened Thunderbird just before I started this, still too soon to see whether any unwanted tabs will open. I'll report back tomorrow as it is late at night here, unless tabs appear quickly, then I'll get back as soon as it happens. Thanks for your patience. Win

This is the next afternoon after the previous email. As above, I successfully followed all the suggested steps. I have just been looking through the Sent Folder and I suddenly have 17 unwanted tabs open. They are all from the Sent folder but I had not clicked on any of them, nor would I have accidentally scrolled past them, they are all from before Xmas and I wasn't looking back that far, they have opened themselves. I haven't been doing any extra deleting for quite some time now, so that isn't the problem. I am just so sick of this. Do you think that uninstalling and downloading a fresh exe file and re-installing would fix the problem? I would prefer to find a solution before going to that last resort. If so, before I uninstall... I have 3 sub-folders in to which I have moved emails I wish to save. How do I save those folders, and will I be able to move them back in to Thunderbird once re-installed? The rest of the mail isn't important to save as it is IMAP and will download again. Also, how do I find my mail account set up details so I can re-establish it? I will have to save my address book, and re-establish the message filters and folders. Thanks Win

re :I have 3 sub-folders in to which I have moved emails I wish to save.

I presume these folders are in the 'Local Folders' mail account.

I would be less inclined to think this is a problem with the program otherwise other people would be reporting plenty of issues with tabs being auto opened. It is more likely to be an issue within a profile.

I would suggest you leave th eold profile as it is and instead create a new profile and add the imap account.

In Thunderbird Help > Troubleshooting Information Under 'Application Basics' - at the bottom see 'Profiles' - click on 'about:profiles' It opens in a new tab.

click on the 'create a new Profile' button Then click on 'Next' Enter new profile name - but 'Default User' offered should be fine and click on 'Finish'

That new profile name will get added to the list in the 'about:profiles' tab and will be auto set as the 'Default Profile'. Below that new profile will be a button 'Launch profile..' - click on that button to open in a new window. Now close/exit the original Thunderbird window. Add the imap account.

Please report when this is done and I'll post info on how to get the 'Local Folders' folders imported over to that new profile.

The 3 extra folders are sub folders of the main account, not in Local Folders at all. Local Folders is totally empty. I am a bit scared of creating a new default profile, in regards to all the work it will entail. As well as the usual "normal" folders, I have 18 subfolders of the main account and message filters set up so that the incoming mail is filtered in to the correct folder. If I create a new profile, all that will need to be done again, won't it? For example, I run a Photoshop group and have a folder for that group mail, and use it as storage for pretty well all of the incoming group mail and refer back to it frequently and I don't want to lose those. In that folder there are currently 3600+ emails. If I set up a new profile, when I download all the imap mail to the new profile, they will all be in the InBox mixed up with all the other emails which are normally filtered to THEIR folders, until I can remake new folders and filter rules? How do I add the IMAP account? Will I need to find out from my ISP what the settings are? The unwanted tabs are still appearing ... I just closed 6... 40 minutes I closed 5. Thanks Win

re :As well as the usual "normal" folders, I have 18 subfolders of the main account Is that account an IMAP mail account ? IF yes: Imap mail accounts show an exact replica of what is held on the server. They are in effect one and the same. Imap account folders cannot be regarded as separate independent copies because the folders synchronise with the server folder and can only display what is held on server. If you create a folder then it is created on the server. If you move an email from one folder to another folder within the same imap mail account, then that email is also moved on the server.

So what you see in the imap account, you should see the same if you logged onto your webmail account via a browser. Logon to your webmail account and check.

Do you have several address books or do you use just the Personal Address Book and the 'Collected Addresses ? If you have several address books then please export them as LDIF files to a suitable location eg: desktop.

I'm not asking you to remove anything. The original profile will stay as it is. But clearly something is very wrong within that profile and so a new profile is required.

This means if you created another profile and create another imap account to same server then subscribe to see all the same folders, you would get a download of everything in those folders that is held on the server.

re :How do I add the IMAP account? Will I need to find out from my ISP what the settings are? Your current mail account will already have all the server settings, so it is easy for you to check them.

• Right click on imap account name in Folder Pane and select 'Settings',
• bottom right locate 'Edit SMTP server' button - click on it.

This will tell you all the current settings for the outgoing smtp server. It will tell you info such as 'Server name', port, Connection security, Authentication Method and user name.

• Make a note of them and the click on 'Cancel' because you do not want to edit anything.
• then select 'Server Settings'.
• It will tell you info such as 'Server name', port, Connection security, Authentication Method and user name. Make a note of them.

You say you are already using an imap account, so set up is identical. After creating a 'New Profile' then you add the imap account. File > New> Existing mail account But when you start a new profile it will automatically ask you to set a new mail account. Enter name, enter email address, enter password, select checkbox to remember password and click on 'Continue'. https://support.mozilla.org/en-US/kb/automatic-account-configuration

re : and message filters set up so that the incoming mail is filtered in to the correct folder. Message filters are stored in the Profile name folder within a mail account folder and so that file can be copied and pasted into the second profile. It does not require a complete rewrite of all the filters.

Thank you for your reply. I am very nervous about completing these latest instructions... lol.. My main question is whether I will have to create the subfolders in the new profile before I download the mail again... and whether the message filters WILL be in the new profile before I re-download all the mail. I just dread the thought of THOUSANDS of emails all landing in the In Box and having to make new filters again. Just clarify for me please.. if I make a new profile, and a copy of the emails are remaining in the original profile, does that constitute 2 lots of storage on the ISP servers? As it is, I am well over what my storage allocation is. It's 2 in the morning here, I won't attempt anything till tomorrow, I need to be able to concentrate.. and I'll wait for your answer to this, before doing anything more. Thanks again Win

re :if I make a new profile, and a copy of the emails are remaining in the original profile, does that constitute 2 lots of storage on the ISP servers?

No. There is only one copy of your emails and they are on the server. Your imap account merely shows you what you have on the server.

re :My main question is whether I will have to create the subfolders in the new profile before I download the mail again No. As previously mentioned you have already created them within the imap account and they are on the server. You just have to subscribe to see them in Thunderbird. Have you logged on to the webmail account to see what you have on the server ? If no, then I suggest you do it because it will you to understand that Thunderbird imap account is just showing you exactly the same as on the server.

re: I just dread the thought of THOUSANDS of emails all landing in the In Box If you have created imap folders and moved those emails into those imap folders then they are not in the Inbox on the server. If you logon to the webmail account you would see this for yourself.

re: Message Filters A copy of these filters already exists in the current profile. So after creating the new profile and adding the imap mail account, I will then provide information on how to get a copy of that 'Message Filter' file into the new imap account in the new profile, so that you do not need to create all those filters again. So, no the message filters will not be there at the start, but this will only effect new emails that arrive in Inbox on server and once the message filter files is copied over, all will be back to normal.

re :storage on the ISP servers... As it is, I am well over what my storage allocation is. If you are close to the max allowed storage percentage quota allocation on the server, then you would need to consider how to increase the percentage you are using on the server. One method is to get copies of imap account emails into the 'Local Folders' mail account, so they are stored locally on your computer and not on the server. Basically you need to remove emails off server, but that is something to discuss and fix later.

Thanks for all the information. I will save it for future use... at the moment it is behaving itself. I deleted HEAPS of messages from the Sent folder, and have started going through the In Box, saving any messages with links I need to a folder on an external drive. By reducing the number of stored emails, it only creates extra tabs on much fewer occasions. I'm sure when I finish deleting more, it will be OK. If it starts again, I'll do as you suggest... so I may get back to you again... lol. Win