It is valid, but mostly useless. The filters, and I assume search, acts on the first instance in encounters and as most emails have more than one received header the result is it fails at least as often as it succeeds.

Matt, thanks for responding. I'm aware of the fact that the "Received" date/time are subject to conflicting/overlapping the info in the email header, but in a previous search using the Date header, the emails in question did display a date/time under the Received column. I'm guessing that this date/time would be the one chosen when searching on the Received header. If I'm correct, then a search of the Received header using that date should result in that email being in the list of found emails. That was not the case. I looked in the header of the email in question and find all occurrences of the different received dates and then structured a search to say that the received date would fall within that range of dates. That search also did not find that email. So I'm beginning to think that searches on the Received header would always be useless, not just mostly useless as you stated. Let me know if you need more details on this.

Matt, thanks for responding. I'm aware of the fact that the "Received" date/time are subject to conflicting/overlapping the info in the email header, but in a previous search using the Date header, the emails in question did display a date/time under the Received column. I'm guessing that this date/time would be the one chosen when searching on the Received header. If I'm correct, then a search of the Received header using that date should result in that email being in the list of found emails.

And it is with that assumption that it all falls over in a heap. What is displayed in that column is extracted to an MSF file by completely different code than any that will be searching/ filtering the mail at the time the mail is received. The filter uses the actual message header so there is no overlap at all. Search, might use either data sources. It probably also depends on which search you use as to which data is accessed. some of the search code is as old as Thunderbird and I doubt anyone has looked at it in decades. Things that work don't see much maintenance usually.

That was not the case. I looked in the header of the email in question and find all occurrences of the different received dates and then structured a search to say that the received date would fall within that range of dates. That search also did not find that email. So I'm beginning to think that searches on the Received header would always be useless, not just mostly useless as you stated. Let me know if you need more details on this.

just how are you managing this? I must assume you are using the Ctrl+Shift+F find to do your searching as I am not aware of a customize option in the other two.

In this context you are dealing with string data, not dates. So how can you structure a string function to check for a range of dates in the header that looks like the one shown below?

My example being the email I received notifying of your post. Because this forum only has to send the email from Amazon to Google, it contains only one received header. But I am not aware of any way to use that data to make a useful search in the date part specifically, hence my view it is mostly useless. But I can search for it containing mx.google.com

Received: from a27-216.smtp-out.us-west-2.amazonses.com (a27-216.smtp-out.us-west-2.amazonses.com. [54.240.27.216])
       by mx.google.com with ESMTPS id 5-20020a170902e9c500b001db7e461d91si3923562plk.545.2024.03.01.12.36.17
       for <unicorn.consulting@gmail.com>
       (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128);
       Fri, 01 Mar 2024 12:36:17 -0800 (PST)

Matt: To answer your one question, I invoke Search by right clicking on the main email folder in the Thunderbird message screen (not sure if this is called the message pane) and selecting "Search Messages". This brings up a search panel and on the search criteria pull-down where there are headers like Subject/Date/To/From there is a Customize item which allows me to add additional headers. I admit that I'm not entirely sure how valid this is, because it doesn't appear to verify that the new header is a valid Thunderbird message header. I discovered this when I initially misspelled Received as Recieved. So while you didn't seem to be aware of this Customize feature, you may very well be correct that this search on Received is not really searching on what I think it is. I just wanted to be able to construct searches that could take into account the occasion where the date on emails on my ISP's mail server is different than the "Date" field in Thunderbird. When I am performing housekeeping on the server to delete older emails in order to avoid me using all of the 5GB storage limit. I should explain that I tell Thunderbird to leave messages on the server until i delete them in Thunderbird. This allows me to be able to read older emails from my phone and my ISP's web server when I'm not at home.

It sounds like I may have to figure out another way to resolve these conflicts between received date/time and the traditional date/time from emails.

The header is not going to work for you.

The fact you misinterpreted my question about how you would structure a filter test on the text string I posted to extract the date bit and do something with it sort of makes that clear.

However I did learn one new thing from that, I found that right clicking on an account name in the folder pane has a search messages menu item. This is the oldest search in Thunderbird which I have always accessed from the Find menu item on the menu bars Edit menu or by left clicking on the entry and using the link on the resulting account page.

But I really do not understand your comment about conflicts. I can see the occasional message that is received and dated a minute or three apart, but nothing significant. Although it is possible if the mail server is having issues getting mail delivered I guess. But that is rare these days with properly configured hosted mail. The days of an email taking days to be delivered are really over.

I am guessing you are using POP, as IMAP always leaves everything on the server. Why not just set the leave messages on the server for a time in days and save yourself a job. If you are leaving the last 30 days for use on your mobile clients, just set in in The account settings for at most 30 days, or even 300 days if that manages the space better.

Matt, sorry for being so late in responding to your last post. I'm going to address 2 or 3 of your comments:

First, you are correct that the use of the Received header is not at all reliable due to the factors you mentioned.

Second, the conflicts between Received time and the time under the Date header that caused me to pursue this solution were a lot more noticeable 2-3 years ago when i began my efforts to delete older emails from the server. I was actually seeing examples from several hours to a day or more. As the emails I'm deleting now are a lot more recent the gaps are more often minutes (as you suggested). I can only guess that my ISP has made some improvements in their infrastructure.

Last but not least, I'm going to adopt your suggestion of setting a number of days to leave messages on the server instead of my labor intensive cleanup method. I might set the number of days somewhat higher, but your point was well taken.

Thanks for your feedback.

I implemented Matt's suggestion:

Quote:

Why not just set the leave messages on the server for a time in days and save yourself a job.  If you are leaving the last 30 days for use on your mobile clients,  just set in in The account settings for at most 30 days, or even 300 days if that manages the space better.

I set the number of days to 1000 in order to leave just less than 3 years of emails on the server. But there are now several days worth of emails that are older than 1000 days still on the server. Why aren't they getting deleted? This is a POP3 server in case that's important. I'm either misunderstanding that setting or something is broken