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Know The Most Common Thunderbird Errors – How to Fix Them

Mozilla Thunderbird is a web-based famous email client that delivers tremendous facilities of packages such as emails, chats, newsfeeds, etc. It manages multiple accounts at a time and easily supports Windows, Linux and OS X platforms. Thunderbird provides many benefits but many errors may occur when working with it. So, here we are talking about the most common Thunderbird errors that one can face during sending or receiving emails using this email client. 

Moving ahead to know the most occurring errors in Mozilla Thunderbird-

Common Thunderbird Errors-

Error 1: Incapable of Receiving Messages

Thunderbird could stop suddenly getting messages. Different reasons behind this might be there such as:

  • Technical difficulties with ISP service status 
  • Account setup issues 
  • Inappropriate Configuration

This issue can be fixed by verifying the Thunderbird account settings: 

  1. Choose Tools in Thunderbird and just go to Account Settings. 
  2. Next, choose Server Settings from the list appearing on the navigation pane. Then, choose Server Settings.
  3. Now check server settings (according to account provider specifications).

Error 2: Corruption in Trash Folder & Delete Messages Trouble

A corrupt trash folder may be the key factor behind the inability to delete an email message in Mozilla Thunderbird. Go through the below steps to fix this error as follows:

Launch the Thunderbird and go to the right top corner, press the Menu button.

  1. Then open the profile folder and pick the Help button >>Troubleshooting Information. 
  2. Now, the screen of the Troubleshooting Information option will appear, hit on the Show Folder button show within the Application Basics. 
  3. Next, the windows then display the profile files.
  4. Exit the Thunderbird application by closing it.
  5. Go to the File Manager tab and open the Mail folder or ImapMail folder based on the POP or IMAP account that you are using.
  6. Now open the folder with the name of the received mail server (such as or
  7. Pick the Trash folder, choose the MSF files and delete them. Trash is also named as  Deleted or Bin in multiple accounts.
  8. Then restart the program Mozilla Thunderbird


  • In the case of IMAP, Thunderbird software can automatically create a new Trash tab.
  • In a POP scenario, go to the Folder List and right-click on the account name, then pick the New Folder. Send the folder name as Trash after that, and hit to confirm on the Create Folder.

Error 3: Thunderbird Unexpected Collapse

If the Thunderbird email client crashes, the Mozilla Crash Reporter will appear asking you whether you would like to submit the details about the crash to Mozilla for processing. Thunderbird crash will happen because of problematic add-ons. You will rectify this problem by upgrading your Thunderbird program periodically.

Error 4: Incapable of sending messages in Thunderbird 

Several users are still unable to send messages even after proper account setup. It may be attributed to flaws in SMTP. Additionally, there may be other factors that limit the sending of Thunderbird Account emails. Several of them are:

  • Blockage of Port 25 by the ISP Internet Service Provider
  • Any Firewall/ antivirus program can block Thunderbird
  • When Thunderbird working in offline mode
  • Email provider sets Captcha 
  • Unacceptable outgoing mail settings in Thunderbird

Error 5: When Server does not Assist Encryption 

  1. Initially, test if the server is supporting encryption. 
  2. If it does, then Thunderbird settings will need to be changed. 
  3. Tap the button Change Settings and then add the right settings.
  4. If it doesn’t support encryption, then tick the “I understand the risk” checkbox and hit the Create Account button to continue further.
  5. Additionally, you can move to a secure connection service provider.

All of these are the most common Thunderbird errors that a user encounters every day. So, to move out of this state permanently, you are advised to move over the other best email client like MS Outlook. For this, you can take help from MBOX Exporter which can quickly transfer all the data from Thunderbird MBOX files to multiple formats for migrating. Then you will be free from the limitations of the Thunderbird. 

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The above-mentioned issues are the most common Thunderbird errors that occur in every Mozilla Thunderbird email client. But to fix this problem, you can shift to other email clients as discussed above. I hope you liked this knowledgeable post. 

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