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IMAP & Using Cached Mailboxes Off-Line / offline (permanently)

Last post 12-07-2017, 23:42 by Alan Candy. 6 replies.
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  •  12-06-2017, 22:41

    IMAP & Using Cached Mailboxes Off-Line / offline (permanently)

    Hello All,

    I would have asked this a bit earlier, but the system wasn't letting me create an account. Some problem with the Captcha system.

    Anyway, I'm here in New Zealand, on the other island from where David lives...

    Some of you have probably heard that one of our major local ISPs has rather suddenly decided to terminate all its e-mail services.  Unhappily, that affects me, as my wife and I both had large collections of e-mail stored there - around 3GB each!

    Of course, the support they offered for downloading this e-mail was fairly ineffective. I'm not a fan of Outlook, and don't know if it could be relied on to do this.  Thunderbird was suggested, but having no great experience with it, wasn't too keen.

    Having been a long time user of Pegasus, I had great faith in its reliability and believe it is solidly coded, so I opted for that as my main platform for this mission.  However, using IMAP off-line was not something I had tried...

    Of course, that's a bit misleading, because once you're off-line, you're not really using it (IMAP), and instead are simply asking Pegasus to open its cached folders for you. If only it were "simply"!

    I read the Help file instructions and it all looked good, so I went ahead.  (I started this project at least two weeks before the deadline, but even that was not enough...)  Downloading this much e-mail was very slow, and took days.

    I found out how to get WPM to download (copy / cache) all messages to the client side. It's not as easy as I'd hoped, as you have to do it folder by folder, but at least you can do a Verify to check how many messages are in each Folder, and that the data is consistent, so that was a plus.

    However,  I have since discovered that in Pegasus (for Windows at least), IMAP Off-Line is not quite what I'd imagined.  I ended up here, and found several threads on exactly this question, none of which seem to have been resolved.

    I have done my own experimenting, and it seems it works like this:


    After downloading (caching) all messages, shutdown and restart Pegasus.

    If required, choose (type-in) the account name to open the desired account. Local folders only, are displayed.

    Go to 'Tools > IMAP profiles...' and select the relevant profile.  Now click the 'Connect' button. 

    If the IMAP server is still there, everything will connect as usual, and all the "remote" (cached) mail folders will be visible.

    Now, to use "Off-Line," Right-Click on the account mailbox icon, and select 'Disconnect this mailbox'.

    Ok, now click the "On/Off-Line" toggle icon near the bottom RH corner of the PM window. You'll get a Red X appear over the Network Tee symbol. Pegasus is now Offline.

    Now, if you go back to 'Tools > IMAP profiles...' and click the 'Use offline' button, you should be able to see all your cached Folder and messages. (This is from memory, unfortunately...)

    Voila, you are now Offline, and able to access all your old mail, off-line.

    The problem is, it seems to me, you cannot get to this Off-Line state, without being able to actually go On-Line first.

    As soon as you shut Pegasus down, you are back to square one. Now that the server is offline, I have not been able to go back Off-Line and open my cached mail...

    When I try this without the mail server, all I get is the account mailbox icon appearing where it normally does, but no folders below it...  I'm hoping I'm doing this wrong!


    Apparently, Pegasus wants to check with Daddy before it will open the door.  But Daddy's gone.

    Obviously, I should have made sure I copied all my Cached messages to equivalent local folders while the server was still live... Silly me!

    Does anyone know how to do that, now?  

    Or, is there some other way to get Pegasus to open the cached files so I don't need to do that?

    I'm running Windows 7 64-bit, with Pegasus V4.72.572 (latest download).


    Hoping someone out there knows this trick! Is there a secret setting / config file switch somewhere that says "Daddy says it's ok"?

    Obviously, there's a flag somewhere inside the code which gets set by a successful connection and folder check, to allow this Offline access to happen later, but how can we set it manually?


  •  12-07-2017, 2:17

    • Brian Fluet is not online. Last active: 01-23-2020, 18:27 Brian Fluet
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    Re: IMAP & Using Cached Mailboxes Off-Line / offline (permanently)

    I don't use IMAP but out of intellectual curiosity I did some testing just to see if I could get a sense of the behavior.  Here are some observations regarding offline mode:

    - In the IMAP Profile, the cache management settings for clearing the caches must not be set 

    - The header cache file for each IMAP folder is created upon closing of the folder.  Each folder must be opened then closed for there to be a header cache.

    - Body cacheing is a manual process (right click on the IMAP folder > Cache all messages)

    - When opening an IMAP profile offline, any IMAP folder without a header and body cache will be listed in the folder list but will be empty when opened

    - Special emphasis is made in the manual about the sensitivity of the cache files to damage.   That isn't very reassuring if considering using the cache files as permanent local storage.

    - The folder information for an IMAP folder shows the location and filename of the cache files but it shows this information regardless of whether the files have been created. So it's not confirmation, it's prospective until creation.  The cache size is displayed so a 0 byte cache indicates that it doesn't exist.

    IMHO, if an IMAP connection is your only option and you need messages stored locally, those messages should be copied to local folders.  Unfortunately that is not of any help to you Alan if you can not connect to the server anymore. 


  •  12-07-2017, 8:06

    Re: IMAP & Using Cached Mailboxes Off-Line / offline (permanently)

    Hi Brian,

    Many thanks for your prompt reply, your efforts and your comments.

    I have to agree with everything you have said!

    I didn't know about the sensitivity of the cache files to damage, but that makes sense, given that they seem to be a kind of simple incremental database. Not terribly reassuring, but not a big issue in normal use.

    There's only one thing I would add. I can't check it now as I can't get my remote / cached folders to open, but Right-Clicking on a cached folder brings up a number of options. As you say, one of those is Cache all messages. Another is (I think) [Folder] Properties, and I think it's that one that offers a Verify button. Clicking that button seems to perform a consistency check on the folder's index/header and body cache files, and reports the relevant file sizes, number of messages and any errors detected. I did all that for each cached folder before I copied them all to DVD, so I feel confident that I have all my e-mail.

    I just can't access it...

    [Oh, while I think of it, I was stumped for a few hours by hitting the 2GB file limit on one of my wife's folders (body cache file). After the second attempt to cache it, I twigged to what the problem must be, and simply moved some of the biggest emails to a new folder.]

    Subsequently, (a couple of days ago) after discovering my off-line problem but before I could post here (and if I may mention this here) I found a rather old, but seemingly still fully operational IMAP backup program called IMAPsize. It's nice in that it creates every e-mail in its relevant folder as a .eml file, named according to subject line, so one doesn't actually need any particular e-mail client for this data to be quite usable. (If not particularly easy to search...)  Pity I didn't think to simply copy to Local folders yesterday.

    Instead, started furiously re-downloading all the e-mails yesterday, but only got about 10% before they finally locked out the server (after telling me I had one more day left...)

    Fortunately, I spent several hours in several phone calls to them over the past couple of days, even e-mailed them screen shots, so they have a good log of my issues. I spoke to them (nicely) again today, and they have agreed to re-enable my access for a few more days.

    Hasn't happened yet, they said it would take 24 hours, but hopefully, it will. And hopefully, all I'll need to do is login, and copy all my Cached folders to Local folders... And Backup again.

    Famous Last Words!

    It does seem a shame that the promise of Off-Line operation perhaps can't be fully realised, but I hope that everyone interested can learn from my mistakes.

    Of course, if anyone does know a better workaround for this, there are a few people who would really like to know!

    Is David still working on a Version 5, does anyone know?




  •  12-07-2017, 21:31

    Re: IMAP & Using Cached Mailboxes Off-Line / offline (permanently)

    FAMOUS LAST WORDS, indeed.  What fun!

    The ISP has re-enabled the requested two accounts. IMAP now re-connects again as normal. Whew!


    Trying to move my first block of messages to a Local folder, I received multiple random, intermittent Insufficient Disk Space popup messages. I don't remember the exact message and didn't screenshot it, but I think it also suggested insufficient permissions. When it first happened, I Alt-Tabbed to check disk space but have a few GB spare. I figure it wouldn't be permissions as I would expect they are all the same.

    I was copying a block of several hundred messages from a Remote folder to a Local one, so I thought I would then receive a new popup for every remaining message, and after clicking OK many times, found that the Esc button cancelled them so kept my finger on that - but then, they stopped and the moving continued.

    When finished, there were no "leftover" messages from the selected block in the source folder, so I'm wondering, did they get lost in the process, or did the move complete successfully?  I guess no one (except maybe David) knows, but I now face the task with trepidation

    I'm running Windows 7 64-bit with 4GB RAM and a 3.3GHz 3rd Gen i3, so nothing out of the ordinary. I guess low memory triggering a Paging File increase might be the next most likely explanation. And a temporary connection failure would give an entirely different result?

    Anyone else ever seen this? 

  •  12-07-2017, 21:33

    Re: IMAP & Using Cached Mailboxes Off-Line / offline (permanently)


    Auto-Bold here as well. The gremlins are getting me today. 

  •  12-07-2017, 22:00

    • Brian Fluet is not online. Last active: 01-23-2020, 18:27 Brian Fluet
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    Re: IMAP & Using Cached Mailboxes Off-Line / offline (permanently)

    I suspect I speak for a number of us when I say that what you are experiencing is one of the reasons why we away from IMAP whenever possible. It's a shame that it's being forced upon us by so many providers

    Alan Candy:
    Trying to move my first block of messages to a Local folder, I received multiple random, intermittent Insufficient Disk Space popup messages.

    Bumping up against the 2GB folder size limit?

    I don't know if "Move" will delete off the server when connected via IMAP but suggest "Copy".

  •  12-07-2017, 23:42

    Re: IMAP & Using Cached Mailboxes Off-Line / offline (permanently)

    Ahh. I didn't know there was any real reason to avoid IMAP. It seems to offer many advantages to me, and I guess, most people.  Being able to access "everything" from almost any device, anywhere, seems very inviting. I found it annoying not being able to access POP e-mails because they had been downloaded to a client somewhere, and I found the "Download only unread messages' option a bit troublesome.  Even then, you still can't access Copies of Sent messages, if they are on your Desktop at home.  I guess a special BCC-self e-mail account is the answer?

    I guess I need to do more research.  One thing I do find troubling is the general move to cloud-based e-mail, which will eliminate many small e-mail clients, I'm sure.  I refuse to give all my e-mail and contacts to Google!  They know far too much already.  On-going, reliable backups from a long time ago would have been the best option!

    In this case, it wasn't the 2GB limit. Only 170MB worth. I think my PC must have been running out of memory.

    You are right!  Move was a dumb idea! I dragged and dropped, which doesn't offer the Copy option.

    Already done an IMAPsize backup. Messy results, from a future lookup PoV. 

    I am going to try a German product next. Sounds ok. MailStore (Home)... 

    Then, will come back to Pegasus. 

    Thanks again for your comments.

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