Thunderbird Community Forum

In event creation in Calendar the options for repeat pattern are daily, weekly, bi-weekly, monthly or yearly. There is an option to create a custom pattern, but if I enter every 28 days, because I want the event to recur every four weeks, it is over-ridden by the option above which is the repeat pattern, daily, weekly etc and the event appears daily. There appears to be no way to create an event that occurs repeatedly every four weeks (28days)?

Can anyone help please?

I've been using Thunderbird on Windows 10 since last year sometime. Currently I'm on version 151.0.1.

I've 4 x mailboxes here and since yesterday, 3 of them show me an unusual message when checking for emails. I tried attaching a screenshot but although the screenshot uploaded, I couldn't find a way to insert it here. But the message says Unable to write the email to the mailbox and asks me to check if I've write privileges (which I have) and to cheek the available disk space.(currently 101GB free).

The message is happening 2 or 3 times each day and lasts for about half an hour, then everything works fine again. Has anyone else seen this??

Hello,

Everything working just fine last night. Wake up and Thunderbird will not retrieve emails.

Remembered this old message I got so I went through and deleted my second email address, didn't help.

https://support.mozilla.org/en-US/kb/thunderbird-and-yahoo

Checked all settings compared to Yahoo, still won't download messages. I can even send a message with my current settings no problem, and it does login, just won't retrieve emails. Gives me a connection timeout.

Anyone have any ideas?

Hello, I have six calendars: five are hosted by one provider, Runbox.com, via SabreDAV, and one is hosted by a different provider, Apple iCloud Calendar. I am periodically seeing the error shown below on multiple calendars during automatic sync.

I have saved a two-day event history from the error console and can provide it on request, along with any other troubleshooting information that may be helpful.

I am technical by nature, but my programming experience was primarily with mainframes rather than personal computers. Could someone kindly help me troubleshoot this ongoing issue?

Thanks in advance.

Bill

10:34:53.958 An error occurred when writing to the calendar House! Please see below for more information. Error code: MODIFICATION_FAILED. Description: If you’re seeing this message after snoozing or dismissing a reminder and this is for a calendar you do not want to add or edit events for, you can mark this calendar as read-only to avoid such experience in future. To do so, get to the calendar properties by right-clicking on this calendar in the list in the calendar or task view. CalCalendarManager.sys.mjs:949:15

   announceError resource:///modules/CalCalendarManager.sys.mjs:949
   onError resource:///modules/CalCalendarManager.sys.mjs:803
   notify resource:///modules/calendar/utils/calDataUtils.sys.mjs:46
   notify resource:///modules/calendar/utils/calDataUtils.sys.mjs:73
   onError resource:///modules/CalCachedCalendar.sys.mjs:95
   notify resource:///modules/calendar/utils/calDataUtils.sys.mjs:46
   notify resource:///modules/calendar/utils/calDataUtils.sys.mjs:73
   notifyError resource:///modules/calendar/utils/calProviderUtils.sys.mjs:689
   notifyOperationComplete resource:///modules/calendar/utils/calProviderUtils.sys.mjs:662
   notifyListener resource:///modules/CalDavCalendar.sys.mjs:720
   doModifyItem resource:///modules/CalDavCalendar.sys.mjs:794

Here is an additional group of errors from the night before:

23:09:52.245 [calCachedCalendar] replay action failed: <unknown>, uri=https://dav.runbox.com/calendars/908506/bill/, result=2147500037, operation=[xpconnect wrapped calIOperation] 23:09:52.249 calendar: CalDAV: No response status doing webdav sync for calendar House CalDavRequestHandlers.sys.mjs:476:16 23:09:52.249 calendar: CalDAV: No response status doing webdav sync for calendar House CalDavRequestHandlers.sys.mjs:495:16 23:09:52.249 calendar: CalDAV: Error doing webdav sync: undefined CalDavRequestHandlers.sys.mjs:528:16 23:09:52.263 calendar: There has been an error reading data for calendar: House. However, this error is believed to be minor, so the program will attempt to continue. Error code: DAV_REPORT_ERROR. Description: There has been an error reading data for calendar: https://p31-caldav.icloud.com/204954917/calendars/home/. It has been disabled until it is safe to use it. CalCalendarManager.sys.mjs:952:16 23:09:52.263 calendar: There has been an error reading data for calendar: House. However, this error is believed to be minor, so the program will attempt to continue. Error code: READ_FAILED. Description: CalCalendarManager.sys.mjs:952:16 23:09:52.263 [calCachedCalendar] replay action failed: <unknown>, uri=https://p31-caldav.icloud.com/204954917/calendars/home/, result=2147500037, operation=[xpconnect wrapped calIOperation]

I added a new mail account and then after a week or so decided to remove it. But after removing it I kept getting a popup nag to enter a password for the removed account.

i manage 8 email accounts for different projects I run.

When I open thunderbird, all my folders in each email open up. Is there not a setting to say don't open folders?

Have been successfully running Thunderbird for many years on Windows 10 on 2 different private computers. Within the last week both computers unable to send and receive messagees. BT E mail account is absolutely fine as can access it via webmail and via Android e mail app on my phone. Login details have not been changed. Have tried updating to 150.1 no joy. When trying to send a message we receive Send Message Error immediately but with no explanation as per attached image.

Mozzilla fonctionne mais je ne peux plus faire "envoyer" mes mails. C'est terrible d'autant que n'y comprends rien . Je rédige-sur la page "Rédaction" et après il n'y a plus de case "Envoyer." par contre je reçois les mails J'ai glané les infos au bout de 2 jours  : IMAP Je sui "Orange" Sortant SMTP/SSL/TLS port 459 Entrant SMTP/SSL/TLS port 995 et quelque part  : version 140.II.Iesr  ? Vous pensez que c'est grave ? ça fait 10 ans que ça fonctionnait

I received a spam message this morning that had a "Disposition-Notification-To" (aka Read Receipt) line that had MY email address on it. I honestly don't know why a spammer would do this - but that's not the issue. I have Read Receipts disabled, but Thunderbird generated an email (to me) and sent it to my mail host. This seems like a bug. Even if the Read Receipt has my email address on it (making it mostly harmless), Thunderbird shouldn't have generated the message. Or am I missing something? Thanks.

Thunderbird version number: 148.0.1 Mail provider: Yahoo Client OS: Windows 10

The issue and steps I tried to resolve: On 1 Jan 2026 I switched from Outlook client on my Windows 10 PC to Thunderbird 146.0.1. I did not import any user data from Outlook but started with a clean install of TB for the new year. I use yahoo.com with POP3 as my email provider. Server Settings: Server Name "pop.mail.yahoo.com", port 995, SSL/TLS, OAuth2 Outgoing Server: Server Name "smtp.mail.yahoo.com", port 465, SSL/TLS, OAuth2

it all worked fine and I was very happy with the setup. Then from early to mid-February I was unable to use my computer. When I finally accessed Thunderbird again, it connected to Yahoo and showed that approximately 800 email messages would be downloaded and started downloading them. After downloading about 100 messages, Thunderbird timed out and I haven't been able to get it to work since.

I have read and followed or tried to follow these articles plus others that I may have forgotten about (not listed in any particular order) - OAuth2 Authentication for Yahoo, AOL and ATT | Thunderbird Help - including all the steps in Please check the following before asking for support - POP access settings and instructions for Yahoo Mail | Yahoo Help - Automatic Account Configuration | Thunderbird Help - Manual Account Configuration | Thunderbird Help - Thunderbird and Yahoo | Thunderbird Help - Send and receive messages in Thunderbird | Thunderbird Help - Can no longer get emails | Thunderbird Support Forum | Mozilla Support - Emails suddenly stopped downloading to Thunderbird 140.2.1esr | Thunderbird Support Forum - Get Messages | Thunderbird Support Forum | Mozilla Support - Cannot receive messages | Thunderbird Help - Problem with Thunderbird working with Yahoo Mail acccounts. | Thunderbird Support Forum

I have removed all messages from the Yahoo inbox and tried to find one or more messages that may be affecting the download. I don't know the best way to determine that.

I use Windows Defender for my antivirus. I don't see anything in Defender that blocks or scans email messages which would prevent downloads, although I could be wrong about that. if this might be the issue, please provide some guidance about how to check Defender.

I have uninstalled and re-installed Thunderbird. In the process I downloaded the setup file for Thunderbird Setup 148.0 and installed that version. It later auto-updated to 148.0.1. Before installation, I removed all external connections from my Yahoo account and completely removed Thunderbird from my PC, including the profile and profile.ini. When I reinstall and switch the account to POP3, Thunderbird captures the App password from Yahoo and connects just fine. But it still times out while attempting the first download of a message. The first several times it timed out, an error message was displayed but now it doesn't show anything. Except no messages are downloaded.

At this point, I don't know what else to try. Since I don't have much experience with Thunderbird, I don't know how to troubleshoot the process (logs to look at, etc.). I don't want to go back to Outlook but I need the email client to work and download messages. Any help would be much appreciated.

Over the last week or so, I have received an enormous amount of scam, but no matter how many times I "train" the filter, it doesn't work.

I have just received another 3 from this site: mid:02guhjkj6-ABMcSHN6Or-JiC-000000@eu-central-1.amazonses.com, which claim to be from Madasafish Security>security@qi9adgongzenElptrum.de

I have tried on several occasions to follow the manual instructions how to deal with the spam, but I find it so log-winded that my non-techie brain, which is not wired for these kind of things, gets tired and I give up. If anyone has a more intuitive approach how to deal with this, I would be very appreciative. I have marked sites multiple times as spam, but the spam control ignores me!

I have all my past emails in specific folders within Windows Mail currently. I have three email accounts. I want to set up Thunderbird and import all the folders of emails into it and access all three accounts from within Thunderbird. I have a Master computer running windows, a tablet and a phone. I would like each device to be able to access all the email accounts and the stored folder tree within Thunderbird. I would like the Master computer to be set up with POP3 for all accounts so I can archive those I need to keep. I would like the tablet and the phone to be able to see and interact with the emails via imap so that when the Master is opened it downloads everything for processing. Do I need to set up each device separately with accounts being either imap or pop3 accordingly? will they all sync together? Thanks for your input.

Hello. I am trying to add a new provider, which means adding a new account. When I click "Add new account" it takes me to a page that asks me to enter my existing account. Does this mean the currently running account or the new account?

Whenever I do anything with email I get a message "not responding" which causes a delay for a few minutes before it proceeds This occurs with almost every action Open email, delete email, browse a different folder (eg Inbox to Sent) it suddenly started happening yesterday

Hello,

I have this problem. On only 1 PC from 5, with same mailboxes installed and same configurations, on one of the mailboxes, Thunderbird does not accept setting to "not read" the letter. I tried making time to read the letter and it worked for 10 min, and then again stopped. At final, no matter how it is set, when I push to read the message it always read it.

Tried repairing the folder, but doesn't work.

Any Ideas will be great.

Thank you