That is not my experience on windows 10. I wake my system and it starts getting messages, I wish it would get them quicker, but it retrieves them on wake up.

Have you tried troubleshoot mode in the help menu to see if the failure is caused by an addon?

Your suggestion turns out not to work for me. I turned off all the addons, exited TB, ran it again. My messages were read. Then I put my computer to sleep and woke it again. My messages were not read this time.

My problem remains, as stated. Windows 10 home, Thunderbird 91.5.0 (32-bit).

Then the next step is to restart your device in safe mode with networking and see if the issue reproduces in that mode of the operating system.

Microsoft offer these instructions for doing so.

I tried. I set msconfig > boot to use safe mode with networking, but when I restarted, networking did not work and there was no list of networks to connect to. I wanted to try restarting from sleep, but could find no way to get the computer to sleep. The usual sleep command didn't work, and closing the laptop lid didn't work. Just curious whether you tested this procedure before recommending it.

I would rather wait for internet connection being recovered. It can take some time before network is ready and in case of vpn there is even more delay. For example putting arbitrary delay after makeup is not a very good solution because may cause sync errors when tried too soon. Look when the windows network icon changes to internet, I guess there is an even for that. in that case it does not even matter it it is after wake up or a connection loss.

I do not understand any of this or how it relates to the suggestion I made here for Thunderbird, sorry. There was no delay in establishing a network connection: there was no list of wireless stations at all. Nor is VPN or anything else that is fancy likely to be available during Windows safe mode by Thunderbird.

Again, my suggestion is that waking Thunderbird from system sleep mode should trigger a download of messages from the accounts. Currently, it does not do so in Windows Home.

I do not understand any of this or how it relates to the suggestion I made here for Thunderbird, sorry.

I relates because that is how it works now, the system returns from sleep and it gets mail. Yours apparently does not. That is a support issue to be diagnosed. Not a missing feature. If you do not wish to pursue that I am more than happy to step away.

My uninformed guess is your computer is relatively slow, with limited memory and is struggling to load the amount of information from disk to restore the memory and re-instantiate a connection before Thunderbird gives up trying. Sleep on a spinning drive can take quite some time to recover from given how inherently slow all spinning drives are. I call it my uninformed guess because you have actually provided no information on the environment you are using.

My feeling is plug your device into a wired connection. Still have an issue? (safe mode also works on a wired connection.) Wired connections respond so much faster than wifi in normal circumstances and are not prone to dropouts and other issues like interference prone wifi is.

Your guesses are good ones, but I am rather familiar with my computer and see it running about as fast as it did when it was new. I have even applied a fix to the "Windows search problem" that loads down some editions of Windows with 50 to 80 percent cpu load running a program called search.exe most or all of the time.

Thunderbird contains a variable for the number of minutes it waits between server message reads. I decreased mine to just a couple of minutes, so TB does read messages after waking from sleep. But it doesn't read messages immediately, only after the couple of minutes pause.

This is different behavior from starting TB in a new process. Starting TB in a new process always reads messages from the servers immediately.

The big evidence that my computer is not morbidly slow is that clicking the Get Messages button doesn't delay even a fraction of a second: it reads messages immediately.

It may be that something is wrong on my computer to cause messages not to be read immediately on wakeup. But the guesses posted here so far are unfortunately incorrect.

Thank you both for your help, and I hope you will please continue helping instead of "stepping away".

I wonder if someone familiar with the TB code could please check to see if TB handles waking from sleep. Note also that Windows itself may fail to notify on waking from sleep (https://social.msdn.microsoft.com/Forums/en-US/5b21ccbf-293a-460c-ae3d-62cad5d2af86/nofication-problem-with-win10-sleep-messages?forum=windowssecurity), so it may be necessary for TB to check the real time to see if it has waked from sleep.