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Thunderbird 102.6.1 caused "Unable to write email to the mailbox" error on all but 1 account

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After opening Thunderbird recently, the software updated to 102.6.1. Unfortunately, I began receiving multiple error messages (I pool 9 separate email addresses together) that it is unable to write email to the mailbox. However, I discovered that one email address can still receive emails. The difference I can find is that the one email address uses mbox message storage, and all the others are using maildir. Unfortunately, the option to change is grayed out so I cannot try changing it to see if that fixes any of the other addresses.

Any help on the next steps?

After opening Thunderbird recently, the software updated to 102.6.1. Unfortunately, I began receiving multiple error messages (I pool 9 separate email addresses together) that it is unable to write email to the mailbox. However, I discovered that one email address can still receive emails. The difference I can find is that the one email address uses mbox message storage, and all the others are using maildir. Unfortunately, the option to change is grayed out so I cannot try changing it to see if that fixes any of the other addresses. Any help on the next steps?

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Have you seen this? https://support.mozilla.org/en-US/kb/maildir-thunderbird after a decade, it is still not really ready.

Do you have an antivirus program installed? Perhaps block it scanning in your profile folder. They can be quite problematical where large numbers of files in a single folder are concerned. They can also have issues with EML files. They are basic text files, but that does not stop them trying to decrypt encoded attachments in each mail to scan those as well. No reason to do that, except for "completeness"

Try using your operating system tools to check the drive for physical or logical errors. See https://answers.microsoft.com/en-us/windows/forum/all/disk-check-windows-10-chkdsk/c1f2fb49-7b71-409d-b713-6c10a28c9e51 When all access to each mail calls for a different physical file issues with the file storage show up very quickly.