Start *Windows'* safe mode with networking enabled - win10 https://support.microsoft.com/en-us/help/12376/windows-10-start-your-pc-in-safe-mode

Does problem go away? Please reply to let us know results.

I'm not sure what you have in mind here. If I start Windows fresh, Thunderbird will be fine, just like it is when I start Thunderbird fresh. The issue is putting the computer to sleep with Thunderbird already open and then waking the system from sleep. When I did that this morning, Thunderbird was taking 13.7% of the CPU and was nearly unresponsive. I killed the task and restarted and it is fine.

After running fine for a while, it jumped back up to over 13% and it isn't really doing anything beyond checking for new mail every 10 minutes since I am working in the browser. It also rapidly jumps round between about 225MB of memory to over 400MB of memory.

And, later, when the high CPU ends ... like 0% or .1%, the memory usage is down to 140MB.

tamhas said

I'm not sure what you have in mind here.

Start windows in safe mode. Then start Thunderbird. Then put computer to sleep....

Well, I tried restarting in safe mode with networking enabled, but when it was up, there was no network so Thunderbird couldn't check for messages. This box is currently connected via wifi ... don't know if that is the issue.

issues I have encountered, but far from exhaustive;

1. Overnight backup not yet complete. (fix backup timing) 2. Over night virus scan not yet complete. (modify anti virus settings) 3. No exception in Anti virus program for the Thunderbird profile folder. (Create an exception https://support.mozilla.org/en-US/kb/profiles-where-thunderbird-stores-user-data) 4. Global index corrupt (rebuild the global index https://support.mozilla.org/kb/rebuilding-global-database) 5. add-on that looses the plot. (usually from folk claiming to improve security, but none are exempt.) Try Thunderbird safe mode.

Not the backup or virus scan. Seems like one would want the virus scan to include Thunderbird ... possibly especially since it is a source of material coming in to the system. I can try the global index thing. Add-ons I have are Add-on Compatability Reporter, Console, Expression Search / Google Mail UI, Send Filter, Signature Switch, and Zombie Keys.

This morning I had the high usage and so I killed the process and restarted. Interestingly, if I kill from the Task Manager it goes very quickly, but if I just close the window, it hangs around for some minutes. During the day today I have seen no further examples of high CPU usage, but I have observed while typing mail or deleting a message, quite long pauses at odd intervals.

If device was sleeping at night then AV might scan computer when it wakes (depending on AV settings).

I can see in the Task Manager that there is no heavy AV scan going on.

The global index rebuild is under way ... I have some big folders. I notice that even though it reported rebuilding Sent for a fair while, Sent is not listed as one of the re-indexed folders in Activity Manager.

Well, almost quitting time and the global index rebuild has finished. Producing a 2+GB file at that. It will be tomorrow whether I see any behavioral changes.

Wayne Mery said

Start *Windows'* safe mode with networking enabled - win10 https://support.microsoft.com/en-us/help/12376/windows-10-start-your-pc-in-safe-mode

If the global index rebuild doesn't help then try the above plus Thunderbird safe mode.

I did start Windows in safe mode with networking enabled, but had no wifi connection so Thunderbird was unable to fetch mail from the server. Didn't seem much of a test.

This morning, Thunderbird was peaking over 15% with nothing going on in the Activity Manager. It seems to be cycling between that and about 4% (compared to 0 to .1% when working normally and not doing the index rebuild). It was only a couple of percent during the rebuilds.

So, it is very busy doing something it isn't telling me about. And, this is after killing the process and restarting.

tamhas said

I did start Windows in safe mode with networking enabled, but had no wifi connection so Thunderbird was unable to fetch mail from the server. Didn't seem much of a test.

Agreed. I've seen other Thunderbird users on Windows 10 report networking not working in safe mode. And https://answers.microsoft.com/en-us/windows/forum/windows_10-update-winpc/windows-10-no-internet-connection-in-safe-mode/742a564b-bc0a-44eb-ac56-a370e968b18d does not have a solution. And I have not found a solution.

tamhas said

This morning, Thunderbird was peaking over 15% with nothing going on in the Activity Manager. It seems to be cycling between that and about 4% (compared to 0 to .1% when working normally and not doing the index rebuild). It was only a couple of percent during the rebuilds. So, it is very busy doing something it isn't telling me about. And, this is after killing the process and restarting.

If there is

• nothing in activity manager
• nothing displaying in the status bar at the bottom of Thunderbird main window
• no active spinner

then it seems unlikely that global indexing is occurring. But I would

• disable global indexing
• disable AV
• set Thunderbird offline at File > Offline > work offline

What are your results?

Also, please explain exactly how you know rebuild activity is occurring, because I don't see that explained in detail.

Footnote, sometimes CPU related to antivirus activity shows up in the application CPU.

If indexing were occurring, would I not see that in the Activity Manager?

Note that, having gotten past the start up and early part of the day, Thunderbird almost always shows at 0.1% CPU activity or less. Every once in a while there is a brief 0.3%. But, then, there will suddenly be a period of something in the neighborhood of 14%. This is fairly extraordinary since when it was doing the global indexing, it would run 3-4%, presumably because the speed of the process was limited by disk activity.

I am skeptical about testing off line since it seems to me that one needs in or outbound activity to trigger something happening. Otherwise, when I am busy in the browser or whatever, it seems like Thunderbird should have nothing to do.

And, I can see the Trend Micro activity in the task manager. It is never more than a fraction of a percent of CPU.

While typing this, I saw another spike to 14% coinciding with a downloaded message and moving the message to junk. I am emptying the junk folder to see if that has any impact.

Incidentally, selecting to delete everything in Junk has pushed CPU utilization up near 15% and the deletion is going **extremely** slowly.

It is not good to make assumptions when we do not yet know the source of the CPU.

https://wiki.mozilla.org/Thunderbird:Testing:Memory_Usage_Problems#Diagnosis_Steps has a list of which many have not been eliminated/explored - several might be quickly found if Windows safe mode worked for you (see DIAGNOSIS item #3 in the wiki, which includes antivirus SW)

I will check out that link after lunch. In the meantime, I will note that my attempt to empty the Junk folder shoved the meter up around 15% and left it there solid. And, after an hour, only 1000 messages got deleted. Or, maybe got deleted. Having killed the process and restarted, the Junk folder shows approximately the same 10,000 when I started the delete. That implies ... if linear ... that it would take 10 hours to delete all the mail. Makes me really wonder if Junk isn't at the core here.

While eating lunch, I tried deleting smaller batches from Junk and got the same kind of performance, i.e., many, many minutes even to delete a few hundred. If I delete similar batches from Trash, it is nearly instantaneous.

Does that suggest anything? Any quick way to empty Junk?

Hmmm. Having deleted a bunch of stuff from Trash, I can now delete far, far more quickly from Junk. Perhaps the thing I should do is to clean up Trash, then clean up Junk and see what happens.