starting at the end. The "repair folder" actually re reads the file that has your mail in it to build a new index that is used by Thunderbird to populate the user interface. SO while the process may have appeared destructive to you, it was not. It was bringing the display into line with reality.

I am assuming your mail is coming in as POP. IMAP users do not see this kind of issue unless things are really messy. In a POP mail situation nothing you do on the server has any effect, except in the case of Gmail. They have options to set the date from which POP mail will download, but they are not very helpful, just exist.

Go back to the Properties pane with the repair folder. How many messages and what size on disk are shown? Go to the troubleshooting information on the help menu. Click the show profile button. Close Thunderbird. In the windows file manager that has opened. Select the mail folder and then the folder named after your mail server (Hopefully there is only one) in there will be a popstate.dat file. Delete it.

There will be a file in the folder called inbox. What size is it? Please make a copy and place it on your desktop. We might be able to get something out of it. If the cause is not anti virus.

Restart Thunderbird. Now all mail currently on the server will download. ALL of it including what you already have.

The usual cause of all mail disappearing is that the anti virus scans mail and decides you have a threat pops up a dialog asking you (or not) if you want it to fix the issue. Clicking yes is the death of the mail file and everything it contains. Sometime if goes to "quarantine" but more often than not it is just erased.

We recommend that the Thunderbird profile folders not be scanned as the anti virus scanning appears to do more harm than it prevents.

Please be sure to answer the questions in bold as you go. That will give a good indication of what "might" be recovered.

Gust as an FYI. I have a local folders inbox that has 32 thousand messages and is sized in the gigabytes. So your was probably not falling over because it was large.

Compacting is the final step in erasing deleted mail. Doing it now would be bad as once compacted there is no going back, Ever. Having said that regular compacting removes old deleted mail from the file so leaves a smaller footprint for the anti virus in a months time to decide something is wrong and want to get rid of it and the file that contains it.

Matt, thanks for your help...

I had deadlines to deal with, so for the past couple of days I haven't done anything more about this problem--and did not run "Get messages" in Thunderbird. I only accessed my e-mail through my provider's Webmail site.

In an effort to see whether the missing messages might appear if most of the thousands of messages in the Inbox were moved into the Archives, I moved all the remaining 2017 messages into the "2017" folder under "Archives". (I already had some 2017 messages there--now there are 2577 messages in that 2017 Archive folder.)

Similarly, I moved all 2018 messaged dated before 11/1/18 into the 2018 Archive folder (which had been empty). That 2018 Archive folder now has 3373 files.

So at this point, when I go to Inbox/Folder Properties, it says "Number of messages: 223" and "Size on disk: 1.5GB". (If I highlight [select] all the messages visible in the Inbox listing, Thunderbird says there are 160 "Conversations", but also says "Selected: 223" and "Total: 223". I don't know what the difference is between "Conversations" and messages, but 1.5 GB sounds like a lot of space for 223 messages. That, at least, is encouraging.

Going to Help/Troubleshooting Information/OpenFile/Mail/pop3.znet.net, I see that the file named "Inbox" shows a size of 1,606,172 KB. I dragged a copy to the desktop, and the copy went pretty quickly until it said "Items remaining: 1 (173 MB)". Then it stopped and said "Can't read from the source file or disk." Retries didn't help.

I had not yet deleted popstate.dat because I thought I shouldn't have Thunderbird download all the messages remaining in my e-mail provider's server until I had first moved all the remaining 2018 (and the few 2019) messages from my Inbox to my Archives folders. I restarted Thunderbird and Archived all the Inbox messages--but I did not let it Compact the folder afterwards, fearing that would limit my options... So at this point, my Inbox showed no messages (they had all been moved to Archives).

Then, going to Inbox/Folder Properties, I see "Number of messages: 0" and "Size on disk 1.5 GB". Going to Help/Troubleshooting Information/OpenFile/Mail/pop3.znet.net, and closing Thunderbird, I see that the file named "Inbox" still shows the same size: 1,606,172 KB. Trying again to dragged a copy to the desktop, I got the same result as before: at the 88% completion point, copying stalled and it said "Items remaining: 1 (173 MB)". Then it stopped and said "Can't read from the source file or disk." Again, retries didn't help.

Looking back to when I first noticed that Compact Folders was not completing, I recall that this seemed to be about how far Thunderbird was getting before giving the error message about not being able to Compact the folders. I'm guessing that there's a point in that 1.5 GB Inbox file that is somehow unreadable (corrupted?), and that's where the process--copying or compacting--stops. Is there any way to fix that kind of problem? And if not, what's the best thing for me to do now?

Note that I still haven't deleted popstate.dat, nor attempted to Get Messages. (And I haven't Compacted the folders, either.)

Please let me know your advice. Again, your help is much appreciated!

Vincent Andrunas

Sounds like you have physical errors on the disk. So you will need to check the volume for errors. The inbox file will be accessible afterwards, but I have no idea how corrupt it will be, or truncated given the error is in that file.

See https://neosmart.net/wiki/chkdsk/#From_My_Computer-5

Matt, I have run chkdsk on the drive several times--I saw no reports of errors, which I suppose means that if there had been any, they have been resolved (or marked as unusable, or something...). Is there a better way to check the drive (or the Inbox file), and possibly repair it? Or am I stuck with no hope of repairing the file? In that case, should I just go ahead and Compact it, and hope for the best? Or delete the file and let Thunderbird start a new one? What's best, here...?

I really don't know how to proceed now. Do I need to just bite the bullet, and abandon all hope of retrieving any incoming e-mail messages between 11/25/18 and late January?

Unhappy prospect, but I don't know what else to do, unless you have an idea...?

Thanks again,

Vincent

chkdsk will do a good job of checking the file system, but in this instance you probably want to run it with the /r /f /b possibly with /X as it is the system volume. That you can not copy the file says there is a physical error.

CHKDSK [volume[ [path]filename]]] /F /V /R /X /I /C [:size] /B /scan /spotfix

 volume              Specifies the drive letter (followed by a colon),
                     mount point, or volume name.
 filename            FAT/FAT32 only: Specifies the files to check for
                     fragmentation.
 /F                  Fixes errors on the disk.
 /V                  On FAT/FAT32: Displays the full path and name of every
                     file on the disk.
                     On NTFS: Displays cleanup messages if any.
 /R                  Locates bad sectors and recovers readable information
                     (implies /F, when /scan not specified).
 /L:size             NTFS only:  Changes the log file size to the specified
                     number of kilobytes.  If size is not specified, displays
                     current size.
 /X                  Forces the volume to dismount first if necessary.
                     All opened handles to the volume would then be invalid
                     (implies /F).
 /I                  NTFS only: Performs a less vigorous check of index
                     entries.
 /C                  NTFS only: Skips checking of cycles within the folder
                     structure.
 /B                  NTFS only: Re-evaluates bad clusters on the volume
                     (implies /R)
 /scan               NTFS only: Runs an online scan on the volume
 /forceofflinefix    NTFS only: (Must be used with "/scan")
                     Bypass all online repair; all defects found
                     are queued for offline repair (i.e. "chkdsk /spotfix").
 /perf               NTFS only: (Must be used with "/scan")
                     Uses more system resources to complete a scan as fast as
                     possible. This may have a negative performance impact on
                     other tasks running on the system.
 /spotfix            NTFS only: Runs spot fixing on the volume
 /sdcleanup          NTFS only: Garbage collect unneeded security descriptor
                     data (implies /F).
 /offlinescanandfix  Runs an offline scan and fix on the volume.
 /freeorphanedchains FAT/FAT32/exFAT only: Frees any orphaned cluster chains
                     instead of recovering their contents.
 /markclean          FAT/FAT32/exFAT only: Marks the volume clean if no
                     corruption was detected, even if /F was not specified.

Matt, today I opened Windows in Safe Mode and ran chkdsk D: /r /f /b. (My System drive is C:--a 240 GB SSN, so the /x switch was not required.)

Chkdsk processed 152,560 files. While processing the Inbox file, it slowed for a while at about 65% through; then picked up speed, slowing again at 72% before picking up speed again and completing the file (plus other unrelated files afterward). At the end, it said:

152,560 files were processed Filedata verification completed. An unspecified error occurred (766f6c756d652e63 470).

...and then it returned me to the command prompt. What's that "unspecified error" stuff?

Also, I had run chkdsk on this drive several times recently from within Windows, and it reported no errors or problems. Why did it claim a clean bill of health for the drive then, but when running it now in Safe Mode (with the /r /f /b switches) it reported (and apparently repaired) errors? Can't chkdsk be trusted when run from within Windows?

I restarted Windows, and Thunderbird.

Then, following your earlier instructions, I again went to Inbox/Folder Properties, where I saw "Number of messages: 0" and "Size on disk 1.5 GB", just like before running chkdsk. And going to Help/Troubleshooting Information/OpenFile/Mail/pop3.znet.net, and closing Thunderbird, I see that the file named "Inbox" still showed the same size as before: 1,606,172 KB. This time, when I dragged a copy to the desktop, the copying completed successfully. Looks like progress!

I deleted the popstate.dat file (after taking the precaution of making a copy), restarted Thunderbird, and clicked Get messages. Sure enough, Thunderbird went to my e-mail server's website and downloaded the 91 messages that were there. (My e-mail service provider had restored a few messages--dating from a couple of days before I lost those two month's worth of incoming messages--from their backup files.) So now Thunderbird has my incoming messages from 1/19/19 through today. But I'm still missing all those messages between 11/25/18 and 1/19/19.

Going to Inbox/Folder Properties, it now shows "Number of messages: 91", and "Size on disk: 1.5 GB" (same big filesize as before...). In the Mail folder, the Inbox file now shows a size of 1,613,776 KB (a little larger than before).

I deleted a SPAM message from among the newer messages just downloaded, and Thunderbird asked if I wanted to Compact mailboxes, saying that it would save about 2.9 GB (I guess this includes space saved in files other than the Inbox [like Trash and maybe Sent...], which must not have been getting compacted either...). Since I now have a copy of the old Inbox file on my desktop, I felt confident in telling it to go ahead--and this time, it completed the Compacting operation like it always used to before my problems began. Now Inbox/Folder Properties reports the 86 remaining messages in my Inbox (I had deleted a few unwanted new messages), and shows "Size on disk: 7.4 MB", which I assume is about right (verified by looking in the Mail folder, where the Inbox file shows a size of 7,582 KB).

So now everything seems to be working properly--but I'm still without the two months worth of incoming messages (11/25/18 to 1/19/19). Is there a way to possibly retrieve them from that old Inbox file that I saved to the desktop earlier today?

Also, I'll soon be replacing my current 1TB D: drive with a new 2TB WD Black unit I recently bought. That should ensure no more file corruption, if my problems were due to surface defects with the current D: drive. Do you have any suggestions about what I should do before I clone the old D: drive onto its new replacement?

Again, I thank you for your help and advice! Now, if I could only find a way to retrieve those missing messages...!

Appreciatively,

Vincent

By the way, I forgot to mention earlier that my antivirus program (Norton Security) has never complained or notified me about any problems with my Inbox file, nor any other files that are part of Thunderbird...

Vincent

ok, you still have your inbox copy.

So open it with a text editor. Given it's size go with notepad++. You will have to download it.

SO open the file, and do a global replace. X-Mozilla-Status: 0008 for X-Mozilla-Status: 0001 and save another copy.

Then create a folder in local folder to put this mess. Install the import export tools addon is you don't already have it. https://addons.thunderbird.net/en-US/thunderbird/addon/importexporttools/

Now right click the folder you created and select importexporttools then import an mbox file. Point it to the edited copy. Now I think you will have a mess of stuff to sort through once the import is completed. If no I will try another approach on your old inbox file.

You said the problem child is an SSD. While I have no experience with them, they do have a finite life. But one thing is that by their nature a "surface test" has trouble because they have built in algorithms to spread the wear as it were. Perhaps look for a utility from the manufacturer. sandisk have a couple, but I would not run one from another manufacturer, because they are essentially and operating system on the controller, not like the old drives on a spindle, when all else failed you could go almost directly to the physical platter.