who is your mail provider?

Charter internet, which i read on Thunderbird on my Mac.

Yeah, the problem is charter. They have a mail server that does not work properly.

If I recall correctly selecting another folder and clicking on the inbox again will make the server download new mail.

Thank you, Matt. I've tried this and seems to make a difference. I have my settings at "check for new mail every (1) minute". Is there a place to choose 0? or does this not matter?

10 or 15 minutes is actually better.

This is the bug where the work for the carter issue was done. https://bugzilla.mozilla.org/show_bug.cgi?id=1360117

It appears from my reading that so far it is only to be found in Daily builds, please install this build. I am assuming a mac is the platform https://ftp.mozilla.org/pub/thunderbird/nightly/latest-comm-central/thunderbird-55.0a1.en-US.mac.dmg

it would be very helpful if you could report on how it goes. A positive result would assist in placing pressure for the fix to be back ported to the release version so everyone gets the benefit.

Thank you. I linked to Daily.app, which you provided. Yes, I'm on Mac. Upon opening, I got message: Incompatible Add-ons (following add-ons are not compatible with this version of Daily and have been disabled: Lightning 5.4.1.1 Checking for compatible versions. "No Compatible Add-ons Found...daily will check periodically and inform you when compatible updates for these add-ons are found." Opening continuing....ok, daily build is in. I will let you know how it performs over the next few days.

Hmm, lightning should have been in the installer... but you can get it here.

https://ftp.mozilla.org/pub/calendar/lightning/nightly/latest-comm-central/lightning-5.7a1.en-US.mac.xpi

If you install the lightning, remove it before you downgrade back to a release build. It has a special place as a binary add-on and only works with specific Thunderbird versions and getting it out of the way before downgrading makes the process much simpler. Downgrading is as simple as installing the release version.

It might also be a good idea to turn off automatic updates as nightly has a daily update with new patches. While I might update everyday, I do not expect everyone to play in the bleeding edge sandpit.

Matt: thanks for suggestions. I see that nothing has changed after a few days of trying. My Thunderbird still doesn't load incoming new email automatically. I saw improvement for the first day, but once I went out of program and back in, I lost the benefit. Let me know if anything else to try occurs to you. I appreciate your input.

are you still using "Daily" or have you reverted to "Thunderbird.: Daily has a white icon like a bird hatching.