Perhaps an anti virus update caused the problem.

To diagnose problems with Thunderbird, try one of the following:

• Restart Thunderbird with add-ons disabled (Thunderbird Safe Mode). On the Help menu, click on "Restart with Add-ons Disabled". If Thunderbird works like normal, there is an Add-on or Theme interfering with normal operations. You will need to re-enable add-ons one at a time until you locate the offender.
• Restart the operating system in safe mode with Networking. This loads only the very basics needed to start your computer while enabling an Internet connection. Click on your operating system for instructions on how to start in safe mode: Windows 10, Windows 8, Windows 7, Windows Vista, Windows XP, OSX

If safe mode for the operating system fixes the issue, there's other software in your computer that's causing problems. Possibilities include but not limited to: AV scanning, virus/malware, background downloads such as program updates.

Matt said

Perhaps an anti virus update caused the problem. To diagnose problems with Thunderbird, try one of the following:

• Restart Thunderbird with add-ons disabled (Thunderbird Safe Mode). On the Help menu, click on "Restart with Add-ons Disabled". If Thunderbird works like normal, there is an Add-on or Theme interfering with normal operations. You will need to re-enable add-ons one at a time until you locate the offender.
• Restart the operating system in safe mode with Networking. This loads only the very basics needed to start your computer while enabling an Internet connection. Click on your operating system for instructions on how to start in safe mode: Windows 10, Windows 8, Windows 7, Windows Vista, Windows XP, OSX

If safe mode for the operating system fixes the issue, there's other software in your computer that's causing problems. Possibilities include but not limited to: AV scanning, virus/malware, background downloads such as program updates.

Starting thunderbird in safe mode made no difference. No internet problems. Restored default bios. Outlook works fine but I hate Outlook. Did a system restore for date before the problem began. No difference.

Looks like T-bird makes a connection to the incoming server - but no mail received. T-bird activity manager says " no messages to download+ but there are.

Thunderbird is the problem I think. Can I reinstall it without losing my messages and filters?

You have not as far as I see started your operating system in safe mode, that is what I would expect to make your mail work as my guess is your anti virus is blocking it.

you can reinstall, but if it fixes it it will still have been the anti virus. I say this because uninstalling and reinstalling Thunderbird does nothing but replace the program. It does not affect settings or data.

pat725 said

Matt said

Perhaps an anti virus update caused the problem. To diagnose problems with Thunderbird, try one of the following:

• Restart Thunderbird with add-ons disabled (Thunderbird Safe Mode). On the Help menu, click on "Restart with Add-ons Disabled". If Thunderbird works like normal, there is an Add-on or Theme interfering with normal operations. You will need to re-enable add-ons one at a time until you locate the offender.
• Restart the operating system in safe mode with Networking. This loads only the very basics needed to start your computer while enabling an Internet connection. Click on your operating system for instructions on how to start in safe mode: Windows 10, Windows 8, Windows 7, Windows Vista, Windows XP, OSX

If safe mode for the operating system fixes the issue, there's other software in your computer that's causing problems. Possibilities include but not limited to: AV scanning, virus/malware, background downloads such as program updates.

Matt said

You have not as far as I see started your operating system in safe mode, that is what I would expect to make your mail work as my guess is your anti virus is blocking it. you can reinstall, but if it fixes it it will still have been the anti virus. I say this because uninstalling and reinstalling Thunderbird does nothing but replace the program. It does not affect settings or data.

Did start in safe mode with networking. No difference. Tried turning off anti-virus, then removing program entirely. No difference. Ran anti-malware program. No difference.

reinstalled Tbird. no difference