Thunderbird Community Forum

Good afternoon,

We are experiencing the following issue.

I work as a Technical Support Engineer at a large company in Russia. All of our branches use Thunderbird as their email client.

Approximately three weeks ago, we started receiving reports from users that their email was no longer working.

After investigating the issue and trying to identify the root cause, we have not been able to find a permanent solution. We have already tried the following:

1. Completely clearing the cache, rebuilding the mailbox while preserving emails, and allowing Thunderbird to re-download all messages. 2. Changing the `mail.server.default.mime_parts_on_demand` and `mail.imap.mime_parts_on_demand` configuration settings to `false`, clearing the Trash folder, and restarting Thunderbird. (This only provided a temporary fix.) 3. Reinstalling Thunderbird and creating a fresh client installation. 4. Using the **Repair Folder** and **Compact Folder** options for every mailbox folder. 5. Several other troubleshooting methods found online, none of which resolved the issue.

According to multiple users from different departments who are not connected to one another, they all describe the same behavior:

Thunderbird stops working for about half a day. Then it starts working normally for approximately 15–30 minutes, after which it stops working again for another several hours. During these periods, no new emails are downloaded, regardless of the size or content of the messages.

When checking the mailbox size in Exchange, it reports:

• 3.56 GB used. The quota is unlimited.

However, on the local computer, the Thunderbird profile folder (`Thunderbird > Profiles`) occupies nearly 9 GB. If we calculate the size of all mailbox folders within Thunderbird itself, the total is approximately 6 GB.

Does anyone have any suggestions on what else we can try?

Has anyone experienced a similar issue or found a solution?

At this point, our employees are unable to work effectively because email is a critical part of their daily workflow, and we have been unable to identify a permanent fix.

Yesterday I downloaded 90 emails from my mail server. Only 5 of them were filtered correctly.

Upon reviewing the remaining 85 emails, I observed that many of them "should" have been filtered. So I opened up the Tools - Message Filters and applied the filtering to the INBOX file.

Almost immediately, all 85 emails disappeared. They were not in the Trash folder, nor were they visible in any other folder or mail box that I could see.

It was recommended to apply the "repair" to the INBOX which I tried; However, all that happened was 318 older emails that I have processed a few days before reappeared in the INBOX. Which interestingly would not sort by the date indicated for the email; they would only sort by subject and sender.

It was further recommended to close TB, and delete the INBOX.msf file. Which I did do. In addition, I also restored the INBOX to the previous days file using my daily backup files. That file shows 101,076 kb of info contained in it.

I reopened TB to find once again nothing in the INBOX, and when I tried to re-run the get msgs aspect, the result was the system telling me there were no email messages to collect.

Yet I know the same 90 emails are still sitting in the mail server system.

Why did this happen?

Where did the 85 emails in the INBOX go to?

Why isn't the set of 2200++ email filters not automatically filtering all emails once they are collected, and distributing them to the appropriate email file folder / mail box?

What recommendations are available to help me resolve this situation and prevent it from happening again?

Also, I have a txt and html file of the 8 Jul 2026 filter report. Why can't I upload said files along with this set of information? Why are attachments only restricted to image files?

Thank

Thunderbird Send message Error Sending of the message failed An error occurred while sending mail. The mail server responded: Must issue a STARTTLS command first. For more info, go to https://support.google.com/a/answer/3221692 and review RFC 3207 specifications. ffacd0b85a97d-47aa0f2186bsm33992962f8f.36 -gsmtp. Please verify that your email address is correct in your account settings and try again.

Note: I could not find the suggested specifications as indicated in the error message!

I did not change anything, the sending error occurred suddenly , all my settings IMAP Mail Server Port 993 SSL/TLS OAuth2 and SMTP Port 465 are still set to default. I changed also the SMTP to an new shown default 587 but non of this settings resolved the problem

When email downloads from my internet server to thunderbird how do I indicate that the message is to be deleted from the server. ie I dont want the message to be in two places . At the moment after reading the email and saving it to a folder I have to log into my internet provider and delete the email.

None of my sent emails are accessible. When I go to the sent folder after sending an email, the emails are not there. Same with deleted emails. When I go to that folder, they are not there. Why is Thunderbird email so overly complicated? I think I need a better email provider. I am only using it because gmail will no longer support 3rd party emails (for my business.)

I am using Thunderbird for my emails since gmail will no longer support my business emails. I was able to access my sent emails up until April and now I am no longer seeing sent emails show up in the sent folder. Please provide easy to follow steps for this. I need to be able to access my sent emails.

Thunderbird shows email messages from the wrong account. The messages show properly in Yahoo website and on other computers using Thunderbird. Concurrent with this new issue, I now get message: Sending of the message failed. An error occurred while sending mail. The mail server responded: "Request failed: Mailbox unavailable. Please verify that your email address is correct in your account settings and try again."

I have verified the settings. Searching for help with Thunderbird, I see references to index files getting corrupt. However, I struggle with the correction procedures. When I right click on the bolded email address, "Properties" is not an option on the drop down menu. I cannot find a "Fix folders" button.

BTW, I did contribute December 17, 2025, it seems like a pretty good way to say "thank you!" Jim

Hello, and thanks for the read...

ISSUE: Every day I have to call the telecom ROGERS that took over for telecom SHAW, turn IMAP and Pop3 on 9 Email accounts (they lost 1). Sometimes the 1 to 2 hors chat w/ a human turned it back on will not last long.

DETAILS:

1. I can receive outside Emails *because I can't send using Shaw/Rogers, checking for Email, just hangs at trying to login in to any of the 9/10 emails.
2. When I can get a support person to check, they tell me that IMAP and POP3 are turned off.
3. They will tell me they re-enabled it. But it doesn't enable for me.
4. It all works OK when using the online webmail Zimbra. However, I need to check 3 of the 9 email accounts every hour, others every 6 hours, and others once a day at boot.

QUESTION: When using POP3, does the setting on my SMTP need a special setting on Thunderbird?.

NOTE: I am complying with "Rogers With Shaw" passing the buck to the Email Client (Thunderbird) by asking here - "Could It Be The Email Client'! And my answer is 'No', because Thunderbird works perfectly with 54 other Email accounts.

Thank for reading this, and for any input you may add, ~r

P.S., I'd like to see a upgrade to this input form that allows us to Preview out Post And, when I started this Post, it alerady had a image from a previous Post

Hi

I have set up Thunderbird with a Zimbra mail serveur (Zimbra serveur 10.1.10_GA_4785) using the EWS new feature of Thunderbird.

I can setup the EWS account. The test of the secured connection to the server is returned valid. But in the mailbox, the list of folder is empty, and I see no email. Interestingly, I can successfully send email from this thunderbird using the exchange server as sending server.

To resume, no emails are received, but sending emails works.

So, I check the request to the exchange server when starting a synchronization : Here the result : Request : <soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/" xmlns:t="http://schemas.microsoft.com/exchange/services/2006/types"><soap:Header><t:RequestServerVersion Version="Exchange2010_SP2"/></soap:Header><soap:Body><GetFolder xmlns="http://schemas.microsoft.com/exchange/services/2006/messages"><FolderShape><t:BaseShape>IdOnly</t:BaseShape></FolderShape><FolderIds><t:DistinguishedFolderId Id="msgfolderroot"/><t:DistinguishedFolderId Id="inbox"/><t:DistinguishedFolderId Id="deleteditems"/><t:DistinguishedFolderId Id="drafts"/><t:DistinguishedFolderId Id="outbox"/><t:DistinguishedFolderId Id="sentitems"/><t:DistinguishedFolderId Id="junkemail"/><t:DistinguishedFolderId Id="archive"/></FolderIds></GetFolder></soap:Body></soap:Envelope>

Response <soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"><soap:Header><ns2:ServerVersionInfo xmlns:ns2="http://schemas.microsoft.com/exchange/services/2006/types" xmlns="http://schemas.microsoft.com/exchange/services/2006/messages" MajorVersion="14" MinorVersion="3" MajorBuildNumber="158" MinorBuildNumber="11" Version="Exchange2010_SP2"/></soap:Header><soap:Body><GetFolderResponse xmlns:ns2="http://schemas.microsoft.com/exchange/services/2006/types" xmlns="http://schemas.microsoft.com/exchange/services/2006/messages"><ResponseMessages><GetFolderResponseMessage ResponseClass="Error"><MessageText>Cannot invoke "com.microsoft.schemas.exchange.services._2006.types.DistinguishedFolderIdNameType.value()" because the return value of "com.microsoft.schemas.exchange.services._2006.types.DistinguishedFolderIdType.getId()" is null</MessageText></GetFolderResponseMessage></ResponseMessages></GetFolderResponse></soap:Body></soap:Envelope>

The parameters ( domain replaced by *** for privacy) mail.ews.server_versions : {"https://zimbra.*******.com/ews/Exchange.asmx":"Exchange2010_SP2"} mail.outgoingserver.ews1.auth_method : 3 mail.outgoingserver.ews1.ews_url : https://zimbra.*******.com/ews/Exchange.asmx mail.outgoingserver.ews1.key : ews1 mail.root.ews-rel : [ProfD]Mail mail.server.server4.ews_url : https://zimbra.******.com/ews/Exchange.asmx mail.smtpserver.ews1.type : ews

Anyone successfully used the new EWS feature with Zimbra server ?

PS : I confirm the EWS connection with the Zimbra serveur by successfully using EWS on Outlook for android.

Due to disk space constraints, I wanted to download only the message headers, not the content. I configured the account, disabled synchronization, and Thunderbird downloaded all the messages with the content. What did I do wrong? The account was configured via IMAP.

I'm running Thunderbird v.115.10.1 on a Mac. All of a sudden, I am getting the following error message when I open up TB or check email: "Sending of password for user did not succeed. Mail server pop.earthlink.net responded: Internal error”. If I exit TB and log back in, I usually don't get the error message again and TB downloads incoming emails. I have no problem sending emails. It is still usable, but annoying because it happens 75% of the time. Any help is greatly appreciated. Thank you. -Dave

Recently (last three days) I have been getting many, many repeated popups with the heading "Login to server pop.mindspring.com failed" then below in popup options:

 RETRY      ENTER NEW PASSWORD     Cancel

I click RETRY After 1-3 of these in succession, the email arrives.

What's the problem?