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I followed https://support.mozilla.org/en-US/kb/moving-thunderbird-data-to-a-new-computer but custom local folders and address book were no-shows.

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I very carefully followed the Mozilla process named in the headline after having tried MozBackup with crummy success. I have an inbox that loaded 88 messages beginning January 1 and Trash, and then Local Folders that consist only of Trash and Outbox. There is no Send or Draft. A whole bunch of custom local folders is absent as is the address book, which was extensive. Nothing is in any of the folders except Inbox, which has, as I said, only 88 messages in it. The file "Thunderbird" profile file size on the flash drive I used was 13.2 GB, so a huge bunch of stuff was included that clearly did not show up---or if it did, I certainly can't find it.

All I want is for Thunderbird to look like it did on the other computer and contain everything that was there. This is what copying the profile from the old computer and pasting it into the profile file on the new computer was supposed to do, right? Maybe I'm missing something obvious or maybe not, but there has to be a fix for this. Note: I can do OK with straightforward stuff, but too technical and I'm in deep water. That's why I was so careful in carrying out the profile move, following every single step without fail.

I very carefully followed the Mozilla process named in the headline after having tried MozBackup with crummy success. I have an inbox that loaded 88 messages beginning January 1 and Trash, and then Local Folders that consist only of Trash and Outbox. There is no Send or Draft. A whole bunch of custom local folders is absent as is the address book, which was extensive. Nothing is in any of the folders except Inbox, which has, as I said, only 88 messages in it. The file "Thunderbird" profile file size on the flash drive I used was 13.2 GB, so a huge bunch of stuff was included that clearly did not show up---or if it did, I certainly can't find it. All I want is for Thunderbird to look like it did on the other computer and contain everything that was there. This is what copying the profile from the old computer and pasting it into the profile file on the new computer was supposed to do, right? Maybe I'm missing something obvious or maybe not, but there has to be a fix for this. Note: I can do OK with straightforward stuff, but too technical and I'm in deep water. That's why I was so careful in carrying out the profile move, following every single step without fail.

Chosen solution

Deleting the Thunderbird folder from Roaming and then pasting in the folder from the source computer did the job: The whole thing looks just exactly the way it should look, the way it did on the old computer. For whatever reason, it simply would not override the Thunderbird folder installed on the new computer but got shunted aside.

Thank you very much for patiently persisting. I needed someone with expertise in this area, and I was fortunate to get it.

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Try the instructions here:

https://support.mozilla.org/en-US/questions/1277268

For best results, update the source computer to TB 68.4.1 before copying the data, and update the target PC to 68.4.1 before running it with the copied data.

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Thank you for the response. I followed the Mozilla-based instructions from https://support.mozilla.org/en-US/kb/moving-thunderbird-data-to-a-new-computer with great care, as I mentioned before. They are a more detailed version of what you suggested. Also, both source and target computers were running TB 68.4.1. There must be some way to get Thunderbird moved without big holes in it.

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I think the best way to ensure all files get copied on the source computer is to right-click the Thunderbird folder, Add to zip (or similar archive), copy the archive to the target, delete the existing Thunderbird folder, then extract the archive to .../Roaming. This method has never failed me.

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Thanks again, but probably most here are more technically competent than I am. (1) What does "add to zip (or similar archive) mean, exactly? What is "zip," and what is "archive"? (2) Would this be an additional step in the process I already tried with only limited success?

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Zip archives are built into Windows 10, it's quite simple, and well worth learning about:

https://www.digitaltrends.com/computing/how-to-zip-a-file-in-windows-10/

Try it with some test files before you apply it to TB.

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I did exactly as you directed---twice---and with great care. The first time produced the same results as I had gotten before. The second time did the same thing. Both computers have the latest version of Thunderbird, and I even uninstalled/reinstalled Thunderbird on the target computer before both of these attempts.

Checking "properties" of the Thunderbird folder in the source computer, I see that it's 13.2 GB with 434 folders. After going through the zipping and unzipping process, the Thunderbird folder on the target computer should be the same, but it's not, with the results---far fewer files and much reduced folder size---zipped or not, being the same in the end.

This is beginning to seem like being on a chain gang breaking rocks with a sledge hammer. What would be doing this? I have enjoyed Thunderbird for years and would like to do so again, but only the latest 100 or so emails have moved, with a huge number carefully organized in various local folders not appearing.

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Is the flash drive formatted as FAT32 or NTFS? If your profile is 13GB, you could very easily have some files larger than 4GB, the limit of FAT32, as TB stores mail folders in a single file.

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Thank you . . . maybe we're getting somewhere now. I checked the properties of the Lexar 128 GB I had been using and discovered that it was "exFAT," not FAT32. I did some quick checking and discovered that exFAT doesn't have that 4 GB file size limit, but the article did say that FAT32 was likely to be more compatible than exFAT---which doesn't help given the file size limit.

But it occurred to me that maybe there would be less chance of mismatch if I used an NTFS drive for the profile move. I just happen to have a 1 TB Toshiba external drive I use for backups, and it has maybe 600 GB open. But I just now noticed that the reformat function allows me to redo the Lexar flash drive in NTFS. I'll do that and try again. Maybe this will work.

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The basic method is not in question, just the execution. Check the file size of the zip file or folder at each stage of the transfer, source computer to drive, drive to target.

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I did exactly the same procedure, only using the NTFS flash drive. Same exact outcome: Little or nothing from the profile on the source computer seems to have showed up.

But I looked at the contents of the Thunderbird file on the target computer this time. Here is what is displayed, top to bottom:

Crash Reports Pending Pings Profiles Thunderbird installs (with a little gear icon) profiled (with a little gear icon) Thunderbird (the zipped file)

I tried unzipping that zipped Thunderbird (sub)file again, but got the same result, and it showed up at the bottom of the list just as before despite having been unzipped (or so the system said). The zipped (sub)file is 8.56 GB, and the Thunderbird (sub)file above it is 26.5 GB with 689 files in 65 folders.

So I tried it again---same result. What seems to happen is that the zipped Thunderbird (sub)file disappears at the completion of the extraction, but a duplicate Windows Explorer page appears with the zipped Thunderbird (sub)file back again. The Thunderbird (sub)file above again was 26.5 GB with 689 files in 65 folders, but the same Thunderbird (sub)file in the Windows Explorer window from which the zipped file disappeared after extraction was 13.2 GB with 434 files in 32 folders, almost exactly what was in the Source computer's Profiles file.

But there is that difference, however: The source computer does not have a Thunderbird (sub)file but has these items listed:

Crash Reports Pending Pings Profiles installs profiles

Does this help to explain anything better?

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The Thunderbird folder must be in the Roaming folder:

C:\Users\username\AppData\Roaming

so you end up with this structure:

C:\Users\username\AppData\Roaming\Thunderbird

The Thunderbird folder contains Crash Reports, Pending Pings and Profiles folders, plus profiles.ini and installs.ini.

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Thank you. Does this mean that I do it yet again, but this time before pasting the zipped file from the source computer into the Thunderbird folder in the target computer, I delete any sub-folder(s) named "Thunderbird" in the Thunderbird folder of the target computer?

And, yes, the Thunderbird folder is in the Roaming folder.

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Just delete the current Thunderbird folder on the target. Place the Thunderbird folder from the source in the Roaming folder.

If your zip file contains just the Thunderbird folder, instead of the contents of the folder, extract it to Roaming.

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Chosen Solution

Deleting the Thunderbird folder from Roaming and then pasting in the folder from the source computer did the job: The whole thing looks just exactly the way it should look, the way it did on the old computer. For whatever reason, it simply would not override the Thunderbird folder installed on the new computer but got shunted aside.

Thank you very much for patiently persisting. I needed someone with expertise in this area, and I was fortunate to get it.

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After more than a week of trying everything posted here and a dozen other sites, I finally got this sucker to work!! Except for one little thing...My Calendar did not show up. There are two folders with calendar data in the final resulting profile that came across, but Calendar did not. Is that a separate add-on or something?

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ncsmith@tampabay.rr.com said

After more than a week of trying everything posted here and a dozen other sites, I finally got this sucker to work!! Except for one little thing...My Calendar did not show up. There are two folders with calendar data in the final resulting profile that came across, but Calendar did not. Is that a separate add-on or something?

Check under Tools/Add-ons/Extensions that Lightning is installed and enabled.