Things that can make startup slow:

• open tabs
• calendars
• gmail "All Mail" folder
• proxies
• high mail volume, esp lots of new mail at startup (you have indicated this is not a factor)
• pop accounts, which are now checked serially rather than in parallel

Thank you for your reply Wayne.

None of the issues you mentioned seem to make a difference. I have done "clean" installs of both TB 128.8.1 and TB 136.0.1 and the issue is there immediately.

Yet previous versions are fine. This is why I am questioning if this is by design, meaning it is designed to behave slowly for some reason.

Zero email on servers. Nothing to download. Still behaves the same.

As far as I can tell, the POP accounts have always been checked serially. You can actually see that happening.

Do you have a large amount of accounts as well? One or two accounts are definitely quicker. Once again, this has not been an issue prior to TB 128.

> As far as I can tell, the POP accounts have always been checked serially. You can actually see that happening.

No, serial checking only started in 128.0 with https://bugzilla.mozilla.org/show_bug.cgi?id=1847137

So part of startup time will be proportional to the number of pop accounts. I don't have that many pop accounts, but I'd guess at least one second per account minimum.

Thank you again Wayne.

Well, I've learned something new today. Looks like my solution is to return to TB 115 or figure out a different way to deal with this. I have never had any issue like this before, except when email servers are down but that has been rare for me. Sometimes I just do a quick check of email and if I shut down TB before the 15 seconds is up TB throws a login error, which is logical. Too many accounts to check one at a time.

Hope others with this issue get to see this information. Maybe there will be a fix in the future; maybe.

Thank you again.

I wouldn't rule out some timing or other issues, even ISP related. A pop log with timestamps would help https://wiki.mozilla.org/MailNews:Logging

Thank you again.

There have been no ISP issues. I can swap TB 115, 128, 136, even 102 and not change anything else, the slowness starts with 128. I have tried other non-Thunderbird clients and they all work just fine. Unfortunately I like Thunderbird. I've used Netscape and Minotaur, then Seamonkey way back and used TB since it's first "independent/official" release. I also used Pegasus Mail alongside.

It's okay. I can just stay with TB 115 until I decide on continuing my use of TB.

Thank you again for pointing out that this was a design change, which is what I originally questioned, and you have answered.

To be pedantic, it doesn't matter if there is no ISP issue or other clients work fine or that there is a design change - improvement might be possible but without data nothing will improve. If you were to provide data in the form of a log then we could assess whether something could be improved in Thunderbird for you and for potentially every pop user. I'm confident you have sufficient skills to do that.

Where do I post the Thunderbird log file?

Did the person or persons that submitted this bug https://bugzilla.mozilla.org/show_bug.cgi?id=1847137 have many email accounts? What was the opinion of speed decline after the change?

Others also found TB 128 slow compared to TB 115. You are part of this discussion.

https://connect.mozilla.org/t5/discussions/thunderbird-s-new-version-128-is-significantly-slower-for-some/m-p/75656

Where do I post the Thunderbird log file? Did the person or persons that submitted this bug https://bugzilla.mozilla.org/show_bug.cgi?id=1847137 have many email accounts? What was the opinion of speed decline after the change? Others also found TB 128 slow compared to TB 115. You are part of this discussion. https://connect.mozilla.org/t5/discussions/thunderbird-s-new-version-128-is-significantly-slower-for-some/m-p/75656

The connect thread is a mashup of different issues, and are afaict unrelated to pop.

https://bugzilla.mozilla.org/show_bug.cgi?id=1847137 presumably is the one which resulted in additional problems, one of which is the regression report https://bugzilla.mozilla.org/show_bug.cgi?id=1911950 - just a couple people are in the same bug report.

Rather than add your startup issue and log to 1911950, I suggest creating a new bug report, because the cause or solution might be different.

BTW, thanks for engaging.

I just remembered, the pop3 log lines in the Error Console should by default have a timestamp. If you don't see the time stamps on the left margin, click the gear icon and do "Show Timestamps".

The timestamp is already in the log.

Just to clarify on the "startup" slowness. This slowness is there whenever you do a check for all email accounts, at any time. The reason I stated "startup" is that is the time all email accounts are automatically checked. I know this can be changed but that's what I've been using for many years until the release of TB 128. TB 102 was by far the best version, for me anyway. It gave me zero problems and was fast. Yes, the UI might be dated (to some) but I'm one that looks at functionality and reliability not how "pretty" something looks. Just some feedback on my years of using TB.

I have reviewed a number of Bugzilla submissions and have decided to pass on pursuing this issue further.

Since this is not a bug but a deliberate design change, I highly doubt there would be a regression issued. It also looks like I'm the only one reporting the slowness, adding to the unlikeliness anything will be done.

I have persuaded three people, non-Thunderbird users, to install Thunderbird 137.0.1 using POP3 so I could have some feedback. All three reported the noticeable slowness. They then installed TB 115.18.0 and the slowness was not there. Two of them have three email accounts and one has four. Far cry lower than my now eleven. In my opinion this negates anything to do with my system or accounts.

My decision is to roll back to TB 102.15.1 since it was by far the most reliable client. I have had zero issues with it. Others may have had issues but I haven't. I would stay with 115.18.0 but is has a few bugs that I don't care for. These bugs have been fixed in a later 128 release.

I'm also testing a different client but that's not for here.

Thank you for everything and I wish a great future for Thunderbird.