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I haven't seen any issues with the Toolbar add-on, but have you tested with only one of those add-ons enabled at a time? Google calendars can be synced without add-ons, starting from File/New/Calendar...On the Network...enter your gmail address...calendars autodetected...enter your gmail password in the OAuth window.

I'll try that, thanks

What is OAuth?

OAuth2 is the preferred authentication method for gmail and Google calendars and contacts. When you authorize access by TB to Google, a token is stored in Saved Passwords in TB Preferences. OAuth2 should be set for gmail accounts for the incoming and outgoing servers; cookies must be accepted in TB Preferences.

Thanks

You might also want to try disabling hardware acceleration in preferences. It is a known cause of slowness and blurry fonts with matched with some video drivers.

I tried this but now Thunderbird is very slow, even without any apps! It is going at 30% speed, almost impossible to use. Even though I have just done a clean install on the PC and reinstalled THunderbird.

Any other suggestions on how I can get it to return to normal?

Thank you

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.

I'll try this, thanks Its odd, as my Dell laptop has the exact same software as all other PC's.

thanks

Hello

I found that Windows Defender made my Thunderbird slow as well. I can't remember exactly but I think it was like a stuttering slowness. Try turn off Windows Defender temporarily and see if that makes any difference.

Regards, Pierre