First, I do not have the answer you seek: all l have are questions. - Have you tried running with McAfee turned off? - Is there a McAfee setting to bypass email checks? - any chance of posting screenshots of the explicit errors you are seeing?

Thankm you for your quickm reply... I'm afraid to run it without McAfee because of viruses... Same answer here... I will try and get a screenshot...

Then verify if mcafee has the ability to bypass email checking. Is there a VPN involved here?

Sorry to butt in, I am in the same age/experience category, and have the same issue.

I followed an advice on here and went into MS safe mode, massive improvement, but, despite requesting safe/network mode version it didn't work, so I had to reboot, and now what? I am back in MS vanilla but the email access is slow.

Update, the messages now arrive quickly, when I click them, but if I try to 'delete' after reading it slows right down again.

Sorry for the delay in responding, but my wife has been in and out of the hospital. I can't solve my Thunderbird problems, but I can solve many life problems with this advice...

                                   DON'T GET OLD!!!

But back to Thunderbird...

As for McAfee, I can't get them to tell me how to use it without checking email. But even if I could, wouldn't I be opening myself up to viruses and the like...? Not a good idea...

Here are the error messages I get when Thunderbird slows down. As far as I can tell, there is no rhyme or reason as to which one I get or when I get it:

(1) The account [my email address] is being processed. Please wait until processing is complete to get messages.

(2) Unable to write the email to the mailbox. Make sure the file system allows you write privileges and you have enough disk space to copy the mailbox.

(3) Messages could not be filtered to folder 'Trash on [my email address]' because writing to folder failed. Verify that you have enough disk space, and that you have write privileges to the file system, then try again.

Here are my comments on each one: (1) I have no idea what this one means. (2) I am the only user on my computer so I should have access to whatever I want. Plus, after awhile it does finish what it's supposed to do so apparently I do have access to my own computer. As for disk space, I have over 650GB of free space so I think I'm safe in that regard plus again it eventually does finish so I guess it found the disk space. (3) see 2 above for privileges and disk space. As for trash filtering again everything eventually works...

There you are. I've given the Thunderbird Community answers to everything except how to turn off McAfee email virus checking which I can't figure out how to do and don't want to even if I could. Any new suggestions or questions? Thanks again...

I will see if I can get another opinion on this, someone who has more technical knowledge on this topic.

PS I forgot to mention that when I'm downloaded email and there's a slowdown, sometimes during that slowdown i can hear my hard drive spin up. At least I think it's my hard drive. I'm not positive because other than at the times during these email downloads I've never heard this sound. On top of everything else it doesn't have to be a lot of email downloading. In fact, it just happened and it was only one message... I have no idea if any of this means anything... Thanks again...

re :McAfee LiveSafe Virus Protection software installed:

When you use Imap account there is a constant jibber jabber between Thunderbird and server everytime you select folders, download, send, move or copy or delete emails. Having an Anti-Virus operating means everything you receive and send gets scanned and on top of that you may find it also scans everything that gets opened, so that means all the files containing emails on your computer. So, using an Anti-Virus causes interuption in processes and slows down everything.

There is very little to gain using an Anti-Virus when it comes to email clients like Thunderbird. Thunderbird by default does not allow any remote content to be enabled, so if you do not enable/allow it, then you have a good level of security from that aspect. Do not click on links unless you really know what you are clicking on. You can check the real location of a link, if you hover over the link and look in the Status bar for info before you decide to click on it. After all you do not want to open something in a browser if it's someone trying to get you to open a bad website. Anti-Virus products are good at warning about trying to open a known bad website. Do not open any attachment if you are not fully aware of what that attachment contains or absolutely certain it really has been sent by someone you know. For example, do not open any attachment which comes from someone allegedly stating it's an invoice when you have not ordered anything from that person. Apply some common sense. Basically emails are safe to view if remote content is disabled and you do not start clicking on bad links and opening bad attachments.

Some Anti-Virus products allow you to make folders and all their contents exempt from scanning. Norton is an example, so it's easy to say do not scan anything in profile X folder. I use Norton 360 which offers good safety when it comes to using a browser, but also allows me to stop it going anywhere near my Thunderbird profile. McAfee stopped allowing this. They only allow you exempt actual files (not folders) which is a real pain because there are loads of files in a profile. It takes a while just to sort it out. Please note: if you allow scanning of eg: mbox files that contain emails and AV finds something wrong - do not under any circumstance allow it to auto fix. AV products do not understand that the mbox file contains possibly hundreds of emails and you stand a good chance of losing a load of emails.

Some Anti-virus products also offer a VPN. Many servers do not like people using a VPN to access server because the server is expecting your IP address and not a random IP address. Servers may stop access because they think someone is trying to hack your account. So, if you have a VPN enabled then disable it or create a tunnel for Thunderbird to use so it by-passes the VPN.

At the end of the day the decision is yours, but one of the main reasons for slowness is an Anti-Virus product intervening the process which may even cause timeouts when connecting to server.

@Toad-Hall, thanks much for adding this insight to the thread. This was beyond me.

Compacting:

Do not confuse 'Compacting' with 'Compressing', they are not the same. Compressing does not lose any data and you may know this as 'zipping' a file.

If compacting is operating then it may make a file temporarilly unavailable.

Explaining Compacting in more laymans terms. When emails are downloaded to eg: Inbox, they are written one after the other to a single text file called 'Inbox'. Senario: I want you to imagine it's like one long text document and each paragraph is a separate email.

When you move or delete an email from that 'Inbox' text document, the email gets 'marked as deleted' and 'hidden' from view, but in reality it is still in that file.

Going back to the 'Senario' - it's like you using a red pen to strike through any paragraph you do not want anymore. As you can imagine, after a while that Inbox text file document can look very messy. What's more, the file is still the same size and as more emails arrive, it's getting bigger. This means the messier it gets the more likely that document is prone to corruption - not something you want at all.

Compacting is like performing a cleanup maintenance job on that text file. It creates a copy of it in the same profile account folder and then only copies all the emails that are good thus creating a new file that has got rid of all those 'red strike through paragraphs'. Then it saves the file and gets rid of the old one. Now you have a much smaller, tidier and quicker to read document.

Do not Exit Thunderbird or use any folders when compacting as it may interupt the process and cause additional issues. It should only take a few seconds.

You may have compacting set up to operate automatically, in which case I would strongly advise that you ensure it asks you if it's ok to proceed, so you know it's going on. Check your Compacting settings:

• Settings > General
• Scroll down to 'Network & Disk Space' section
• Under 'Disk Space'

To use automatic compacting:

• Select 'Compact all folders when it will save over' and choose amount eg: 20MB
• Select 'Ask every time before compacting'

(I suggest you perform compacting on a small number eg: 20MB as it will be much quicker to operate and also means it's done frequently to reduce risks)

If you want to compact manually then do not select either of the above. Instead, manually compact the following folders on a regular basis - Inbox, Drafts, Junk/Spam, Trash because those folders get the most moving/deleting activity. Obviously do others after you have performed those kinds of activity. To manually compact:

• Right click on folder and Select 'Compact'

If you use an Imap account then you can auto set to compact the Inbox on Exit.

• Account Settings > Server Settings for the account
• Bottom right under 'Message Storage'
• Select 'clean up (Expunge) Inbox on Exit'

Please note if you select that option, I would advise that after exiting Thunderbird you need to allow some time for background process to complete before you shut down the computer or log off account.

Slowdown can also be caused by files that are larger than necessary. Advise: Regardless of whether you want to use auto compacting or not - Please perform some manual compacting now on these folders in this order to tidy things up. Junk/Spam, Drafts, Inbox, Trash.

Note: Files that are getting rather large even after compacting are also somewhat risky because you have tons of emails in just a single document.

Advise: Please create new folders or subfolders and move emails to improve organising and create much smaller files which are quicker to access. Remember, after moving emails to compact the relevant folder.

re : As for disk space, I have over 650GB of free space

It's not about how much free space you have on the actual drive. If a text file eg: Inbox gets too large then a lot of RAM memory will be used when computer tries to open it. So, if compacting several massive files then computer will suddenly be working very hard and may even crash under some circumstances. Or even if computer is trying to open those files in order to write a new email to it there could be a problem. Hence you are seeing error messages saying there's not enough space to open it or cannot write to the file etc.

Strongly advise you to create more folders and subfolders to sort/organise emails. It keeps file size down and improves performance. Archive older emails by year and folder, so they are not bloating files you use on a regular basis. Manually compact folders as advised in previous comment.