I use Thunderbird 128.6.1esr (64-bit) on Linux and have a mailbox file that got damaged subsequent to a folder repair attempt. The mailbox file size report approximately 2,4gb and should contain approximately 853 individual messages, but when importing the file into the Local Folders only 5 messages are displayed. I tried the following recovery methods to no avail: 1) Using the "Repair Folder" function in Thunderbird. 2) Importing the damaged mailbox file into Apple Mail. 3) Importing the damaged mailbox file into a clean Linux build with Thunderbird 128.6.1esr (64-bit). 4) Importing the damaged mailbox file into a clean Microsoft Windows 10 build using Thunderbird 128.6.1esr (64-bit). 5) Using "mbox2eml" in effort to convert the messages to EML format and then importing the result into a new Local Folder. 6) Using "cutmbox" to split the damaged mailbox file into smaller portions and importing the result into a new Local Folder. Any and all advice shall be greatly appreciated!