re : I have downloaded about a dozen versions from different sources You should only download from the official webpage. https://www.thunderbird.net/en-US/thunderbird/all/

Since version 68, thunderbird has been a dedicated profile per installation, so you cannot simply install another version and hope it will work, it is likely not to locate a profile and instead create a new one. You have to use a specific method when trying to use an older version than has previously been installed.

Also, update to 78 changed all the formats of the address books, so that is also another thing that would need fixing if going back to a previous version.

Can you please tell us what different versions you have tried?

In Thunderbird

• Help > Troubleshooting Information
• In 'Application Basics' it will say 'Version' is it 78.7.1 ?
• Update History - click on 'show update history' button to provide some information.
• Near the bottom - click on 'about:profiles' which opens in a new tab
• Make window big enough so all data is shown - then create an image and post image into this question in forum so we can see what options you have stored and what is currently selected.

re: it stopped What stopped? We need a bit more information about what you mean by 'stopped'. Thunderbird would not launch, so never opened? Or Thunderbird opened but could not access any server? Did you get any error messages? If yes, what did they say? Did this 'stopping' occur after an update? Was that a computer update or a Thunderbird update etc?

In Thunderbird - I cannot answer these I no longer have the program on my computer and I cannot download/open a new one - I get the same msg each time "Your Thunderbird profile cannot be loaded. It may be missing or inaccessible."

It was version 78.7.1

Thunderbird would not launch, so never opened? - current problem Did this 'stopping' occur after an update? - yes a mail provider (Telus) update.

   Help > Troubleshooting Information

   In 'Application Basics' it will say 
   Update History - click on 'show update history' button to provide some information.
   Near the bottom - click on 'about:profiles' which opens in a new tab
   Make window big enough so all data is shown - then create an image and post image into this question in forum so we can see what options you have stored and what is currently selected. 

re :I cannot answer these I no longer have the program on my computer and I cannot download/open a new one - I get the same msg each time "Your Thunderbird profile cannot be loaded. It may be missing or inaccessible."

If Thunderbird was not installed, it would be impossible to start something that did not exist.

So Thunderbird is obviously installed and launching.

But the message "Your Thunderbird profile cannot be loaded. It may be missing or inaccessible." just means Thunderbird cannot use the old profile for some reason. This is probably because you have 'tried a load of other versions'.

re :Did this 'stopping' occur after an update? - yes a mail provider (Telus) update.

That statement would imply at this point there was nothing wrong with Thunderbird program and the profile was fully working, but you 'stopped receiving and sending emails' perhaps because 'Telus' email account needed to update server settings etc to comply with the mail provider (Telus) update. So, Thunderbird itself had not stopped.

This is the sort of information you need to be supplying. I need you to confirm that what I've guessed is correct.

Based on this, I have no idea why you suddenly started uninstalling and reinstalling various versions of Thunderbird, but due to dedicated profile pre installation, it sounds like Thunderbird is now confused hence why it cannot find a profile.

Assuming you are using a Windows OS:

• Windows key +R
• Type %appdata% and press enter.

In the 'Roaming' folder you will see a 'Thunderbird' folder

• If 'Thunderbird' program is running then close it now.
• Then copy that 'Thunderbird' folder to an external device as your backup.

• click on the 'Thunderbird' folder to see contents.

I need you to follow instructions to post some information. You will see two files:

• installs.ini and profiles.ini
• Open those files using Notepad to see contents.
• Then create and post images OR copy paste all contents of those files into this forum question.

• click on 'Profiles' folder'
• Post an image showing the contents of the 'Profiles' folder. It will contain the names of all your profiles.

• Click on the name of the profile which you have been using and contains all your old accounts etc, so you can see contents.

you will see a load of files and folders including 'Mail' and 'ImapMail'

• I need you to locate this file: compatibility.ini
• open 'compatibility.ini' file using Notepad.
• Then create and post image OR copy paste all contents of that file into this forum question.

I will then check those files details to see if there is some out of synch and report back to you.

Whilst waiting for my response I need you to check out this information. The 'Telus' update is likely to be due to the following information: TELUS is migrating all customers to an upgraded email service. We are partnering with Google...

• https://www.telus.com/en/bc/support/article/telus-email-transition-general-info

Have you followed their (Telus) instructions on migrating the account? If no, then you must do it now. Once the account is migrated you need to create a new existing mail account in Thunderbird. But we need to sort out Thunderbird first and then you can use the information also provided by Telus as set out below. At following link see section 'Interactive step-by-step guide for setting up your email app' Select device eg: Windows PC Select program eg: Thunderbird Follow instructions.

• https://www.telus.com/en/bc/support/article/set-up-email-on-devices

[8216C80C92C4E828] Default=Profiles/n60mcj40.default

[D78BF5DD33499EC2] Default=Profiles/n60mcj40.default

[FBB1106297B45314] Default=Profiles/meu8fw5o.default-release Locked=1

[Install8216C80C92C4E828] Default=Profiles/n60mcj40.default

[InstallD78BF5DD33499EC2] Default=Profiles/n60mcj40.default

[Profile1] Name=default-release IsRelative=1 Path=Profiles/meu8fw5o.default-release

[Profile0] Name=default IsRelative=1 Path=Profiles/n60mcj40.default Default=1

[General] StartWithLastProfile=1 Version=2

[InstallFBB1106297B45314] Default=Profiles/meu8fw5o.default-release Locked=1

And after this you lost me, sorry!

The first image shows the Roaming/Thunderbird/Profiles folder only has one profile folder called 'meu8fw5o.default-release'.

Is that correct, I would have expected it to have 2 profiles. 'n60mcj40.default' 'meu8fw5o.default-release'.

'n60mcj40.default' was the original profile in use. If this profile name folder is no longer in the 'Profiles' folder then this explains why Thunderbird could not open it. Did you delete that profile ? Do you have a backup of that profile name folder?

meu8fw5o.default-release is the newest profile Are you certain the current version is 78.7.1 and you downloaded it from this webpage: https://www.thunderbird.net/en-US/thunderbird/all/ where you chose preferred language and downloaded the one suitable for your operating system?

The last image is the list of Firefox profiles so not relevant.

(Telus) instructions on migrating the account - I did this months ago when they first migrated with Google, everything worked fine in TB until a few weeks ago and no one knows why it stopped and now Telus will not help, all they say is that they do not support TB and send you said instructions where I keep getting the same message "Your Thunderbird profile cannot be loaded. It may be missing or inaccessible."

I searched both my computer and the TB backup neither contain 'n60mcj40.default' only the 'meu8fw5o.default-release' I tried downloading from your recommended site 4 more times today: English (Canadian) English (Canadian) Windows 64-bit, Windows MSI 64-bit, Windows 32-bit and English (US) Windows 64-bit.

In case I was not getting the correct one. Each time I removed the previous and got one of the attached messages.

So still have no TB!

lets look at those last images.

The first one talking of a file called exe.part. That would indicate to me you have a defective anti virus that is corrupting downloads, or you are trying to execute it before the download is complete. I have no idea which.

The second sounds like you have managed to download a corrupt windows installer package (see my last comments here) But I would not recommend using the MSI package anyway. It is really intended to corporate installs and lacks some install options the EXE has.

The last is Thunderbird complaining it can not find your profile or it is damaged.

Given the last two were damaged files I guess the same applies to your Thunderbird profile. It might be an anti virus, or it could even be your hard disk is failing and not storing files properly.

So lets create a new profile. it will not have any of your previous information in it, but it will resolcve the error.

use the windows key+R type thunderbird -p tell it to create a new profile in a new folder in the existing profiles folder. Continue to Thunderbird and set up your account

Thank you, Matt, it worked just fine and now TB does as well!

Woops, I thought all was good in TB but I have an empty address book - any ideas how to recover that? I do have folders with email back til 2013!

Okj so there is definitely an issue with your old profile. but lets test that.

goto the troubleshooting information on the help menu select the about:profiles entry. select the n60mcj40.default entry that should be displayed use the button under it to Launch profile. Does it give an error message? what is it? does another Thunderbird launch will the missing profile data?

For Matt -

To your inquiry: select the n60mcj40.default entry that should be displayed use the button under it to Launch profile. Does it give an error message? what is it?

This is what I get: "Your Thunderbird profile cannot be loaded. It may be missing or inaccessible."

2 others that came from somewhere when I was doing above???

I do not understand this - "does another Thunderbird launch will the missing profile data? "

thanks, M.

The 'n60mcj40.default' profile: Previously you posted an image of this location: C:\Users\maidi\Appdata\Roaming\Thunderbird\Profiles folder It only showed one profile called 'meu8fw5o.default-release' Since then you have created another profile called: 'n8njlbx.Default TB'

The 'installs.ini' and 'profiles.ini' info you provided says you have installed at least three different versions of Thunderbird. AS those files contain the info on profile name they look for it.

The Appdata\Roaming\Thunderbird\Profiles folder does not contain the profile name folder called 'n60mcj40.default' and that's why Thunderbird cannot find it.

Please confirm there is no profile name folder called 'n60mcj40.default' in Appdata\Roaming\Thunderbird\Profiles folder.

That's why I asked if you had a backup of your Appdata\Roaming\Thunderbird folder or even a backup of your 'n60mcj40.default' profile folder, so it could be copy pasted back into the correct location.

Do you have any backup ?

Check your computer 'Recycle Bin', does it contain a folder called 'n60mcj40.default' ? Check your Anti-Virus , has it quarrantined a folder called 'n60mcj40.default' ?

If you do not have a backup of n60mcj40.default profile and it does not exist in computer 'Recycle Bin' nor able to be found in 'Anti-Virus', then you wil need to accept whatever was in it is lost, but if you used imap accounts then you can recreate imap accounts and get hooked up to the server again.

You seem to have two profiles that claim they are in use and cannot be deleted. This makes me think you have at least two versions of Thunderbird and each is using a different profile.

When you look in the following locations what do you see: C:\Program Files\ C:\Program Files (x86)\ do you see a 'Mozilla Thunderbird' folder in either location? do you see more than one? Have you installed a version of Thunderbird in another location like a different drive ? Post images of what you see.

If you search for thunderbird.exe how many are discovered on your computer and where are they located ?

Note that last set of images you posted , the first one shows contents of the 'about:profiles' folder. Where it says 'Root directory' : C:\Users\maidi\Appdata\Roaming\Thunderbird\Profiles\n60mcj40.default There is no 'Open Folder' button which indicates there is no folder in that location. If you can locate a copy of that n60mcj40.default folder then we can pasyte it back into that location. Note: here : C:\Users\maidi\Appdata\LOCAL\Thunderbird\Profiles\n60mcj40.default is NOT a copy of your profile name folder.