Thunderbird Community Forum

Every 2 to 3 weeks the Thunderbird Calendar gets wiped out, ie all entries deleted. Once it occurred right after an update. A few hours later it will reappear. Why does this happen and what's the remedy to stop this?

To my new computer Thunderbird has just fetched the INBOX-mails from the IMAP-server, not my many subfolders, not the SENT-folder, not the SPAM-folder. This has previously worked when I changed to a new computer. How do I get Thunderbird to transfer these mails.

I'm looking for an email solution for my husband and Thunderbird looks promising. However I'd really appreciate input from this community regarding our specific scenario before I make a move. I have a programming background but I fumble blindly trying to be his email admin.

The problem we are trying to solve is his current email setup chokes on send/receive almost daily, after which he has to use Task Manager to kill a hanging Outlook.exe process. After years of tinkering I'm about to give up on Outlook completely. I think the main issue is how Outlook interacts with his Archive. His Archive.pst file is 4GB and Outlook saves it as one big file even though it has many subfolders which are essentially his filing system. Outlook is configured to save everything directly to a local laptop which is backed up regularly and we want to retain this local feature. Thunderbird is attractive because: 1. it supports the local drive storage 2. it appears to have options for transferring his Outlook archive and other folders over in such a way that he can continue to search and access them as needed. He would also like to be able to: 1. move new emails received in Thunderbird into the same (transferred) archive subfolders he has now 2. send and receive new emails without the program choking 3. view and send new emails from his Android phone (without accessing the archive) 4. transfer his email contacts from Outlook and manage them in Thunderbird Can anyone see red flags with this in Thunderbird? He does NOT use:

- Outlook Calendar (we synch our phone calendars to Google calendar online)
- Outlook Tasks

Technical Details (in case it matters):

- HP Pavilion 2021 laptop running Windows 10 with 1TB storage (200+ GB free) and 16GB RAM
- Likely to upgrade to a newer bigger laptop with Windows 11 this year
- Outlook is running from a Microsoft 365 subscription
- His actual email account is from gmail but is named per a domain name I purchased
- His Outlook account is setup using IMAP
- We use ESET for virus protection and NordVPN for WIFI security

Any comments or advice are greatly appreciated!

I recently changed my password for Spectrum e-mail and setup my Thunderbird e-mail with the new password, and when I try to get messages on Thunderbird it asks for the password, goes through the login procedure then then returns with the error message "Login to server mail.twc.com with username tppm.ca.rr.com failed." with "retry", "enter new password", and "cancel" buttons.

There used to be a menu in the message header (lower right of screen) that included viewing the message source. I accidentally deleted it and cannot find how to restore it. I have looked through the Config editor and main menus and cannot find an option.

I'm new to using the Thunderbird email client but I find the UI very sluggish and almost unusable compared to Outlook email for MAC.

Running on mac osx 12.7.6. Anything I can try to speed things up.

I currently am using Thunderbird Version 128.8.1esr, Mac OS 15.3.2 As of 3/21/25 no new emails. I have two other accounts in Thunderbird that were not affected. I am now getting the following failure message. Anybody else having new messages not showing up since then? Tom

4 days ago, the calendar app suddenly stopped working. If I try to add an event, it sends an error message saying 'An error occurred when writing to the calendar Sandra Kanfer Clarke! Please see below for more information.' and tells me 'modification_failed' and that '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.' At this point, the calendar switches itself to 'read only' and I get the exclamation mark and triangle saying this calendar is momentarily not available. This is a synced Google Calendar that has been running on Thunderbird for several years without any problems. I uninstalled the calendar and reinstalled it, I uninstalled Thunderbird and reinstalled it - none of it makes any difference.

Trying to send (redirect) a Thunderbird message using Simple Mail Redirection results in an error: "Transaction failed Unauthorized sender address. 1M8Pmu-1u0qJD3qDo-000B18. Please check the message and try again." Is there a fix for this or is there a better add-on for redirecting multiple messages at a time?

Thanks, Doug

2 weeks ago I could send a group email, Now it says not of the form user@host I have an older version 128.8 I believe. The term mailing lists is never used. I have given all recipients the same nickname.

I am not able to send a group email. I was able to 2 weeks ago. The error message is not on the form user@host. I have an older version of thunderbird 128.8 i believe. They do not use the word mailimg list only accounts and I have given the people on the list a nickname and it worked 2 weeks ago

I have a correctly working Thunderbird, with around 15 email accounts connecting to different servers, on 1 Windows PC. I moved the setup to a new Windows PC as described here: https://support.mozilla.org/en-US/kb/moving-thunderbird-data-to-a-new-computer ("alternative method"). Thunderbird version is 128.8.1esr on both PCs. On the new PC, Thunderbird gives a timeout connecting to any of the IMAP or POP3 servers. I have disabled the Windows firewall and uninstalled a McAfee virus scanner. When I restart Thunderbird in troubleshoot mode, everything works correctly (!). However, when I select "disable all add-ons" and "Reset toolbars and controls" + "Make changes and restart", the connection timeouts again occur. What can I do to make Thunderbird behave correctly as in troubleshoot mode?

The contents of my thunderbird folders are not shown although the number of email contained there is shown at the top oof thunderbird next to the folder's name (see images 1 and 2 for example). When a new email comes I can see it, but after clicking on it and seeing it, it disappears from my folder. Nevertheless, all emails are there because if I go to the troublshouting mode I see then (see images 3 and 4). I do not have any special extensions or themes (see extensions.jpg and Themes.jpg).

Any ideas on how I can resolve this issue? Best, Haris

Since a couple of days I have the follwing 2 problems: 1. I can't update my google calendar from TB and changes made in the android doesn't show in TB 2. The message moving function doesn't work. Messages disappear from the inbox but wont show in the folders where they should have been moved to.

I have TB 128.8.1esr(32-bit)

I've tried the troubleshooting steps outlined in the FAQ but have not been able to send any email messages. This just started a few days ago and I've tried these things with no luck:

• Disable firewall
• Disable anti-virus
• Change SMTP settings
• Change email account PW

Windows 11 Norton 360 NordVPN

I don't know if this has any bearing on the issue, but at the same time as I began having trouble sending email, I attempted to install the UPS label printer software. It also looks like there was an update to my AV/Firewall software, but since I have disabled both, as well as disabling the VPN, and there's still no success, I'm ruling those out for now.

NOTE: I have no trouble sending or receiving email with my phone, so I tend to thinnk it's not the account settings. I've tried using the phone as a hotspot to send from my PC but that also was not successful.

Thanks in advance for any assistance!