Install something like https://www.jam-software.com/treesize_free.

Run it against your profile directory[1], sort the list by size, expand the imapmail and Local Folders to show ONE level of directory details and post a screen shot of the treesizefree display.

Also, what are the file names of the 3-4 largest files that you find, and the sizes?

[1] Help > Troubleshooting > Profile Folder

Attached screenshot. Not sure how to find largest 3-4 files. Seems Thunderbird is the largest of all.... Thanks!

the following is unrelated to the original poster's problem

there are Windows tools, that allows to use zip files as folders. so whatever is inside the folder, is actually inside a zip file, compressed. saves lots of space . very useful for saving long text files , text log files, etc. should be great for emails as well. search for "Zip Compressed Folder" , or "Zipped Compressed Folder". once the driver is loaded in OS userland, then all ZIP files becomes a folder. can't recall its name.

anyway , last windows supports it & builtin ( no other tool is needed).

Create a Compressed/Zipped Folder in Windows: • select a folder that you'd like to zip. • right-click on the folder, select "Send to", & select "Compressed folder(zipped)". • a new zipped folder will appear in your Desktop. • this can be used in TB.

create Compressed/Zipped Folder in macOS: • create a new folder on your Desktop or anywhere else. • right-click on the folder > Compress. • a new zipped folder will appear in your Desktop. • this can be used in TB.

lets assume i have a yahoo "mail-account" in TB (IMAP based access)

TB main menu > Tools > Account-Settings > select a mail-account > Server settings > scroll down to bottom into "Local Folder". it may show something like this in Windows, for-example: "C:\Users\<WindowsUserName>\AppData\Roaming\Thunderbird\Profiles\xxxxxxxx.<profile-name>\ImapMail\imap.mail.yahoo-1.com" it can also be written like this: "%APPDATA%\Thunderbird\Profiles\xxxxxxxx.<profile-name>\ImapMail\imap.mail.yahoo-1.com"

the mail-account in TB which you will work-on , create same email sub-folders under "Local Folders" in TB. transfer all emails (by using TB) from mail-account's each email-folder , into the corresponding sub-folder inside "Local Folders". Also write down each email-folder's name under that mail-account.

exit from TB ( close TB ).

copy the Compressed/Zipped-Folder item from "Desktop" , and paste into this location: "%APPDATA%\Thunderbird\Profiles\xxxxxxxx.<profile-name>\ImapMail\" folder. delete existing folder "imap.mail.yahoo-1.com" rename the Compressed/Zipped-Folder into "imap.mail.yahoo-1.com"

start TB.

again transfer, all emails, from each subfolder in "Local Folders" into mail-account's corresponding email-folders, by using TB.

It may be a zip... But the question is why so large? Is every email plus attachment packed away here? It's probably a huge backup file.

Can't imagine every thunderbird user experiences this? It's half my ssd?!!

i updated my previous post , see again.

when a TB user selects the option "File Per Message" in TB advanced settings , and if user adds a new mail-account, then that new mail-account's each email is a single file (it will include attachments inside the that single file, i think). normally all emails & their attachments etc are kept inside a single file per folder.

you MUST Backup your TB-"profile" first (before doing below), into an external storage, (as you dont have sufficient space inside internal storage).

WITH YOUR OWN RISK+WISH YOU MAY DO BELOW . PLEASE DONT BLAME ME FOR ANY DATA LOSS.

do "Compact Folders" option in TB, it will take some time but can ERASE / remove duplicates and all old+unnecessary backup copy & hidden emails. when user deletes or moves email then TB actually marks email in previous folder as "hidden", instead of completely deleting the email.

goto all TB-profile's parent folder, here: "%APPDATA%\Thunderbird\Profiles\" backup the entire above "Profiles\" subfolder. then you may do "Compact Folder" in TB. more info : see+follow the link inside this answer here Note: When you delete messages in an email client such as Thunderbird they aren't physically deleted. Even emptying the Trash does not get rid of them. Instead they are marked for deletion and hidden from view. They are not physically removed until you "compact" the folder. This is a tradeoff done to improve performance in large folders. Messages in a Trash folder aren't actually deleted messages, when you delete a message in a POP account it copies the message to the Trash folder and then deletes the original. When you empty the trash it physically removes (expunges) the messages in the Trash folder. You can't undo that. you cannot uncompact . cannot undo this. unless you have a backup.

TB = Thunderbird.

Attached screenshot. Not sure how to find largest 3-4 files. Seems Thunderbird is the largest of all.... Thanks!

There are NO zip files involved here.

And DO NOT DELETE ANYTHING.

I don't think we need to do more to get the names of the largest files, they are already listed in treesizefree. But for the sake of education, in treesizefree right click on the aol-1.com directory and pick open. A windows file directory window will appear.

The questions that need answers is:

• what is the size of your aol inbox as shown in aol's web interface?
• why are there nstmp files in your account directory. There should not be any. It could be related to the size of your Inbox, it could be related to antivrus or other interfering software. What AV and backup software do you run?

You can recover about 75GB by deleting the nstmp folders:

http://kb.mozillazine.org/Nstmp_folders

I agree with sfhowes this is compact related. To clarify my earlier comment, if compact failed more than once already I am concerned it is likely to happen again - which is why I asked about AV. It would be nice to nail down why this happened now, while the information is fresh.

If the combination of AV and incomplete compacting is leading to unnecessary nstmp bloat, I would first disable AV scanning of the TB profile folder (a general recommendation), then rebuild the Inbox by deleting the mbox and .msf files, restart TB, and have the Inbox re-downloaded from the IMAP server:

http://kb.mozillazine.org/Compacting_folders#Real_fix

Hi, No AV other than what's with Win10.

Should I just uninstall and delete everything ...start fresh? I'm not sure how I feel about moving all inbox messages to new folder then deleting inbox. Instructions say NOT to move the emails back once the new inbox is created. I need it all together, ideally.

Attaches screenshot... nstmp files seem to be the issue.

Any thoughts? Thanks!

Hi, No AV other than what's with Win10.

Any automated backup software?

Hi,Should I just uninstall and delete everything ...start fresh?

No point to do that IMO.

I'm not sure how I feel about moving all inbox messages to new folder then deleting inbox. Instructions say NOT to move the emails back once the new inbox is created. I need it all together, ideally.

No point to that either IMO unless the root cause has been identified. And, related, you still haven't answered the question - what does AOL think the size of your inbox is - is it really on the order of 29gb?

If it should be much smaller than 29gb, then it is possible that TB has downloaded messages multiple times into the Inbox. (I've seen this before - it wouldn't be visible to you, the only clue is more space used than necessary)

Attaches screenshot... nstmp files seem to be the issue.

nstmp files are a symptom, not a root cause.

Only BU is dropbox, but not sure that I have TB on the list to be backed up. Should I delete the nstmp files? What's the difference between nstmp-1 and nstmp-2?

What's my next step? Thanks!!!

Sure, delete the nstmp files. use shift+delete so they don't go to your Windows recycle folder.

-N is just a sequence number to make the file name unique. other than that there is no significance.

> What's my next step?

To recap:

• no automated backup software
• using Windows Defender antivirus
• no solid conclusion on what is causing the nstmp files, but on the positive side it isn't happening frequently (maybe compact got interrupted by shutdown/reboot/loss of power/whatever), maybe it will never happen again

One possible next step is add an exclusion into Windows Defender for the Thunderbird profile directory.

Hate to sound like a broken record, but was does AOL think the size of your Inbox should be? Or if you cannot determine that, what does AOL think is your total storage usage?

I don't know what AOL thinks about storage size. If I go to aol.com... my email is all there...years of it. That said, in my folder:

C:\Users\Howie\AppData\Roaming\Thunderbird\Profiles\160l2vky.default\ImapMail

I have imap.aol.com and imap.aol-1.com and imap.aol-2.com

Does TB create 1 and 2 once the prior fills up to capacity... Or is this the back up interruption that you are pointing out. Initially, when I was setting up TB, there were may times that while all the emails were loading, my computer would go to sleep or lose internet.... was a few day process to get 10,000's of emails stored.

Do I delete ALL or some of the imap.aol.com files? Do I delete ALL or only some of the nstmp files?

Thanks

Not sure if my reply posted??? Anyhow, Do I delete all or some of the nstmp files?

I also have in this folder: C:\Users\Howie\AppData\Roaming\Thunderbird\Profiles\160l2vky.default\ImapMail

imap.aol.com , imap.aol-1.com, and imap.aol-2.com files. Does TB create 1, 2 once the prior fills to capacity or is this from the interruption that you mentioned? Do i delete these imap.aol.com files?

Thanks

Forgot to mention that if your Inbox is actually 20+GB, and you decide to rebuild it and download from the AOL server, it will probably take a long time, especially if AOL has daily download limits. A better method is to access the account on the AOL site, create a new folder e.g. InboxOld, and move all but about the newest two thousand messages or less there. Then, as long as InboxOld isn't a subscribed folder in TB, downloading the Inbox should go quickly, and it's size will be much more manageable for compacting and other operations.

The imap-N folders probably represent folders for the account as it was added and removed several times. Check which folder corresponds to the current setup by looking at Tools/Account Settings, Server Settings, Local Directory.

C:\Users\Howie\AppData\Roaming\Thunderbird\Profiles\160l2vky.default\ImapMail\imap.aol-2.com

So, if the local directory is ---> imap.aol-2.com can I DELETE the imap.aol-1.com and imap.aol.com files? It seems the "aol-1" is 100GB! Yikes!

You can certainly delete the nstmp folders, but then I suggest you first move the aol-1 and aol folders to a location outside of the profile folder, then run TB to ensure nothing is lost before deleting them for good.

I did exactly that, moved the file out to my desktop and eventually uploading it to my Dropbox as a backup. I probably should have noticed how many files, emails, I had before doing so... With so many emails stored over the years it's hard to tell what might be missing.

I noticed that TB says it's downloading message number x out of 22,000. So clearly moving that file did something. My hope is that it'll bring back in those files in a more organized manner... And not take up a 100 GB.

Thoughts?