Hi, my name is ***** ***** i will be taking over for your other expert.
Many experts do not like to give bad news, nor do i. What you are facing is kind of a deletion.
Once thunderbird compacts them, this is what happened:
You cannot undo compacting, there is no such thing as "uncompacting". Compacting physically removes messages marked for deletion and hidden from view. Once they're gone, they're gone. Usually when somebody asks how to "uncompact" a folder they lost messages due to compacting. Sometimes the messages were already gone, but that wasn't noticeable because they were still listed in the folder listing. Other times compacting a folder physically removed messages it shouldn't have because the folder was too corrupt.
This guide is going to explain to you exactly what happened, and also how to change your settings so this
doesnt happen to you again if you choose to move forward and reset the compacting settings.
This guide will show you how to go through your deleted emails as well (i know this isnt your issue)
and will show you that if it wasnt deleted and it was compacted, they are not there anymore.
Sometimes a resolution is not what we want the outcome to be, but i did not want you to have to
wait for an answer due to it being bad news. I also wanted to avoid you researching to find an answer
that is going to end up in there is not a fix for this after the fact. I have left you guides on how to change the compact
settings and troubleshooting for it as well.
If you have any further questions, please let me know.
Please rate the 5 stars at the top of the page to close out this question as it is the only way i am
credited for the work done with clients. Or, reply to continue if further troubleshooting is necessary.