IMAP or POP? (I'm anticipating the latter as IMAP doesn't have a "leave a copy on the server" option.)

Hi Zenos,

Sorry, I didn't see your reply till today.

Yes, it is POP.

Thanks, Mike

"Leave a copy on the server" is a bit of a kludge, and is something of an uncomfortable fit with the operating principle of POP.

POP collects your messages in your behalf; you download them to your email client, clearing the server as you do so. It was designed at a time when email providers could not afford to be generous with email storage space, so they gave you a limited storage capacity and expected you to clear it regularly. "Leave on server" seems to be a later-added feature to help users who wanted to work email through multiple computers.

I can't see any specific support for "leave on server" in the RFC. What might happen is that when set to do so, the client simply omits the DELE command after having downloaded a message using RETR. It does seem improper that a server should then unilaterally delete a message when it hasn't been explicitly told to do so. But some servers do have a time limit after which they remove things. That's a "read the small print" thing.

I would look at the config editor in Thunderbird to see if there is any sign of a "leave on server" setting, and if so, see if it is in the appropriate state. Occasionally the settings in Thunderbird seem to become out of step with their visual controls. (Right now, I don't have any POP-connected accounts to check for myself.)

Failing that, i'd unset the settings, close and open Thunderbird, set the settings, close and re-open Thunderbird and check if that had "taken" this time. But I'm a bit surprised that it might be happening concurrently on three different accounts.

Hi Zenos,

I checked my settings and found the following that seem to have anything to do with deleting emails. I only included server 1 out of 3:

mail.server.default.canDelete;true

mail.server.default.delete_mail_left_on_server;false

mail.server.default.delete_model;1

mail.server.default.leave_on_server;false

mail.server.default.num_days_to_leave_on_server;7

mail.server.default.retainBy;1

mail.server.server1.ageLimit;30

mail.server.server1.cleanupBodies;false

mail.server.server1.daysToKeepBodies;30

mail.server.server1.daysToKeepHdrs;30

mail.server.server1.delete_mail_left_on_server;true

mail.server.server1.keepUnreadOnly;false

mail.server.server1.leave_on_server;true

mail.server.server1.num_days_to_leave_on_server;14

Can you tell me which one(s) should be changed?

Thanks, Mike

I use pop, so checked your settings against mine. Mainly the same or expected possibilities. However the first line you mention: mail.server.default.canDelete;true Is this in bold type as if a preference set by you?

In my config editor, the following line is NOT bold, so it is the default setting and not a preference set by me. I have this: mail.server.default.canDelete;false

It was bold and set to True. I changed it to False so that it is now not bold. I saved that and closed Thunderbird. I re-opened Thunderbird and checked email again, but it still deleted everything on the server.

What server? I think we should actually look at the whole picture.

Despite the assumptions that it may be improper for the server to delete mail other than through the pop DEL command, it is not unusual at all for server administrators to impose their own constraints on server storage.

I manage the email system on Zoho.com and have not set any restrictions that should cause these deletions. It was working just fine before my computer hard drive crashed and I had to restore the email files. From that point on, I have not been able to stop the deletions after downloading.

Just an oddball thought. Do you have anti virus scanning incoming email? Try turning it off.

Yes, I've always had antivirus scanning on my email accounts. That has stopped me from opening several virus emails. But it only alerts me to them and identifies, it doesn't delete them. I have to manually delete the infected emails.

Like I said try turning it off. You never know when something that sits astride a process will fall onto the process and scramble things. We are always looking to the application that is having an issue "suddenly" and usually without "any change" but rarely look to the anti virus as a possible cause even though is is updated daily.

Hi Matt,

Ok, I turned off the antivirus and tried downloading my emails, and again it deleted them all from the server.

This was a little more than just a sudden change. My hard drive crashed and I had to do a barebones re-install from the OS up. After installing Thunderbird and then restoring the mail folders from my backup is when it started. It's like the restore copied over something or made it so that I cannot turn off the delete from server switch.

Thanks, Mike

Please add the troubleshooting information to your post (or at least the the account information part) To find the Troubleshooting information:

• Open Help (or click on three-line-icon and select Help)
• Choose Troubleshooting Information
• Use the button Copy to clipboard to select all. Do not check box "Include account names"!
• Paste this in your post.

Hi Matt,

Here it is:

 Application Basics

   Name: Thunderbird
   Version: 52.3.0
   User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.3.0
   Profile Folder: Open Folder

             (Local drive)
   Application Build ID: 20170815040357
   Enabled Plugins: about:plugins
   Build Configuration: about:buildconfig
   Memory Use: about:memory
   Profiles: about:profiles

 Mail and News Accounts
   account2:
     INCOMING: account2, , (none) Local Folders, plain, passwordCleartext

   account4:
     INCOMING: account4, , (pop3) dynamicwebshop.com:995, SSL, passwordCleartext
     OUTGOING: , dynamicwebshop.com:465, SSL, passwordCleartext, true

   account5:
     INCOMING: account5, , (pop3) dollardynamics.com:110, plain, passwordCleartext
     OUTGOING: , dynamicwebshop.com:465, SSL, passwordCleartext, true

   account6:
     INCOMING: account6, , (pop3) dynamicwebshop.com:995, SSL, passwordCleartext
     OUTGOING: , dynamicwebshop.com:465, SSL, passwordCleartext, true

   account7:
     INCOMING: account7, , (imap) dynamicwebshop.com:993, SSL, passwordCleartext
     OUTGOING: , dynamicwebshop.com:465, SSL, passwordCleartext, true

   account8:
     INCOMING: account8, , (imap) imap.zoho.com:993, SSL, passwordCleartext
     OUTGOING: , smtp.zoho.com:465, SSL, passwordCleartext, true

 Crash Reports
   https://crash-stats.mozilla.com/report/index/bp-78e75785-f13f-4836-bba6-bacfc0170818 (8/17/2017)
   https://crash-stats.mozilla.com/report/index/bp-53de2235-ed66-4f50-9340-928980170805 (8/5/2017)

 Extensions
   Manually sort folders, 1.1.1, true, tbsortfolders@xulforum.org
   Sticky Password extension, 8.0.12.127, true, {54affe52-8223-453b-be1e-2fe2e250045c}

 Important Modified Preferences

   Name: Value

     accessibility.lastLoadDate: 1506405642
     accessibility.typeaheadfind.flashBar: 0
     browser.cache.disk.capacity: 358400
     browser.cache.disk.filesystem_reported: 1
     browser.cache.disk.smart_size_cached_value: 358400
     browser.cache.disk.smart_size.first_run: false
     browser.cache.disk.smart_size.use_old_max: false
     browser.zoom.full: true
     dom.apps.reset-permissions: true
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     font.name.serif.el: Cambria
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     gfx.direct3d.last_used_feature_level_idx: 0
     mail.openMessageBehavior.version: 1
     mail.winsearch.enable: true
     mail.winsearch.firstRunDone: true
     mail.winsearch.global_reindex_time: 1505596493
     mailnews.database.global.datastore.id: df75f760-8301-4208-895d-530e3fc6d6d
     mailnews.database.global.views.conversation.columns: {"threadCol":{"visible":true,"ordinal":"1"},"flaggedCol":{"visible":true,"ordinal":"3"},"attachmentCol":{"visible":false…
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 Graphics

     GPU #1
     Description: AMD Radeon(TM) R5 240
     Vendor ID: 0x1002
     Device ID: 0x6611
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     Drivers: aticfx64 aticfx64 aticfx64 aticfx32 aticfx32 aticfx32 atiumd64 atidxx64 atidxx64 atiumdag atidxx32 atidxx32 atiumdva atiumd6a atitmm64
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     Driver Date: 10-25-2016

     Features
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     DirectWrite: true (6.2.9200.22164)
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     Version in use

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     NSS S/MIME
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I forgot to mention that it deletes the mails from the server all of the above accounts.

And they are on two different servers and email systems.

account 7 and account 8 are IMAP accounts, so the content in Thunderbird and the content of the server are synchronized. Thunderbird can not be deleting anything from the server without deleting the mail from the account in Thunderbird. This can occur when IMAP mail is moved to Local Folders, but otherwise the two must synchronize.

I really have my doubts about that sticky password extension. How does it do password management better than Thunderbird's own password manager. I would think it was a good way to find trouble really.

The A record in DNS appear to be missing for the dolardynamics domain and the dynamicwebclients domain.

Will these affect things with Thunderbird negotiating through your anti virus? I really have no idea. They are problems that may just be red herrings, but you do need to fix them at some point. As an incorrect a record can have an adverse effect on mail delivery.

So I suggest we go to a low level log of the pop interactions between Thunderbird and the server using the instructions here.

You will need to modify the example by changing the IMAP to pop3

set MOZ_LOG=POP3:5,timestamp

The log will become huge in a very short time. so I suggest you allow only one fetch of mail and then restart Thunderbird normally. open the created log file and look for DEL commands in the text. if they are not there then Thunderbird is deleting nothing. If they are there we have at least confirmed the source beyond any doubt.