Your messages will be written to disk at some time, so of course some disk IO is inevitable. But email messages tend to be in the 10s or 100s of Kb size range, so shouldn't consume a lot of IO time.

What AV are you using? AV may require messages to be written to temporary files for the purposes of scanning, doubling up the amount of IO.

How much system RAM do you have? Are you perhaps running into page swap issues?

Hi Zenos:

Thank for for your reply and I apologize in not getting back to you sooner as I had some testing to do first with some intervening interruptions.

Anyway following your hints on a possible cause I removed or changed everything on my PC that had protection capabilities. I switched from my current AV to Defender, the MS Firewall was already being used with my other AV.

I deferred using TB for a few days so that my emails built on and would need to be downloaded. After a reboot I started TB, deleted a few older emails and proceeded to write a new email. After a few lines the new email window went into a non-response situation. From that point on it was impossible to do anything in the window.

the status bar showed that down loads were in progress. It would switch between various folders but the brunt of the downloads were in the all mail folder, about 60 of them. While this was happening I wen to the main TB window ahd tried some basic things but that window went to Non-Response mode or simply did not respond to a mouse click.

Next I went to my other PC and checked my I-Net speed which was over 150 Mbps. I next went back to my laptop (which is where TB was running), started a browser and using the same software did the same Speedtest, (the Speedtest.net browser plugin) which was again over 150Mbps.

Next I just waited until the downloads completed and once they did the disk IO light when off or was slowly blinking and I was able to complete and send my email.

It seems to be that one of the following could be the problem: 1. If the AV is the cause then even Defender can not be used. 2. the process of downloading is the cause and not the AV 3. writing many emails to the various folders may be the cause

Maybe there are other possibilities I don't know about.

As an FYI at other times while trying to isolate this problem I've used the MS Process Explorer in an attempt to id the culprit that is doing a lot of disk IO or paging IO. When running TB with no other application if I sort the dispaly based on page IO TB is always at the top of the list.

I know that my system is memory constrained (4GB) but that doesn't seem to be the problem. Once the downloading stops the Disk IO light goes back to its normal blinking rate and things work better (given the age and size of my laptop that is).

Hopefully that gives you or someone more information to do some further investigation.

Regards,

Cheech

I have found that if I set Thunderbird to startup offline and then click the two monitors to bring it online that things go better. But there does appear to be some sort of processing bottleneck in the get all mail process that does not release control as I would think it should.