From MozillaZine Knowledge Base
When downloading new mail, you may receive the following error message: “Unable to write the email to the mailbox. Make sure the file system allows you write privileges, and you have enough disk space to copy the mailbox”.
There are three reasons which are known to cause this error:
- 1) corrupt folder
- Your mail folder could be corrupt due to not compacting it often enough. See compacting folders.
- 2) EncFS
- This problem has been seen with every incoming email from multiple accounts - when the Mail folder resides within an EncFS-encrypted folder. Although this error is seen, a single email will be downloaded successfully. Email can be re-checked repeatedly, and the error just keeps popping up after each email. This was reproduced with Thunderbird 18.104.22.168 (20070117) and EncFS 1.2.3. The workaround is to move the Mail folder into unencrypted space, and then create a symbolic link pointing to it. Then Thunderbird can check email properly again. -- Sy
- 3) an old bug
- However, this bug has been marked as resolved for some time now.
- This error can occur if Thunderbird downloads a message from a certain kind of POP server which contains a certain combination of control characters in the message body.
- You can work around this bug by reading and deleting the message using webmail (so that Thunderbird won't see it as a new message), and then checking for new mail again. The only way to prevent it from happening is to use a POP server with better support for Thunderbird. If you are using your ISP as your email provider you might consider signing up for a free email account somewhere. This isn't meant to imply that there is anything wrong with your current POP server.