Slow syncing with IMAP

I have seen some of the posts regarding this issue including this one
Which is close to what I am experiencing.
Just deleting two email can take a little while, I tried deleting over 6000 and it took most of the night.
While this is happening EM Client locks up and my computer is unusable as it locks up periodically for up to 5 minutes at a time then frees for a while then locks up again.
I understand the time it takes to sync with external servers but was wondering if EM Client can be set up to process in the background using less priority on the computer resources.
This will hopefully free up EM client to carry on with other things including sending receiving and reading emails etc. It would also help with preventing my computer from locking up. 

To add to this the syncing is very slow for new incoming emails as well.

IMAP in Outlook was this slow but in Thunderbird is extremely quick.

I like eM Client as it appears to merge the functionality of them both and means I don’t have to have two email clients but the slow syncing is quite unbearable.

I haven’t tried yet but would like to know if I use the “download messages for offline use” does it download to the local folders or will it keep the same folder structure as the IMAP structure and will it update on the remote server if I delete emails folders etc on either. I don’t want an offline “copy” of the online information I would like an offline replication of the online info.

Sorry for the novel.

Just downloaded a 14Mb attachment it took 34 minutes. Same attachment in thunderbird took 2 minutes.
Please help me set up the most efficient way to run eM Client

I have also set up a pop3 account and transferred all my emails over from Outlook.
After the entire transfer is completed this account too is painfully slow in even previewing emails and these are on my hard drive not on an external server.
I would have thought that it should be instantaneous as it is not having to sync with an external server.
Sorry for all the posts, I have the 30 day trial with looking to purchase if suitable so want to fathom out all the go with it.
Speed & usability is very important to me.

Hi Grant,

You shouldn’t have to experience this slowness of eM Client. Normally it’s fast. I don’t know the cause, but I assume someone of eM Client will reply to you soon.

Hi Grant, what version of eM Client are you currently using? What mail service are you using with eM Client (is it an / AirSync account)?

Thank you,

Hi Paul,

Thanks for the reply.

I have 4 accounts I am trialling, 2 are pop3 and 2 are imap gmail accounts.
They are all running in the one instance of eM Client.

The two pop3 accounts were imported from outlook (local hard drive) and appeared to stuff up during the transfer as everything was duplicated many times in the local folders of eM Client. When I say many, I mean at least 50-100 times and that is everything, mail, calendar, contacts etc. So much so that my hard drive filled up after leaving eM Client to do its thing overnight and eM Client returned an error cannot complete transfer.
I was guessing that this may having something to do with it slowing down, I deleted everything in the local folders as it appeared that the two email accounts did transfer successfully to their own folders.

At the moment I cannot tell you what version I am using as when I started up this morning it said emptying trash “This operation may take a while to complete”, so far it has been over an 2 hours and the eM Client window does not open so is not usable.

This message appears very regularly, when moveing or deleting emails, calendar events etc. which to me suggests that the development team agree and accept that there is some lag in the software.

No problem there but why not do it in the background with low resource use, no need for message and user can carry on.

Same thing for sending emails, do it in the background so it frees up the software to carry on working. Make it appear to the user that the email has been sent as soon as the sent button is pressed.

I downloaded eM Client two days ago and it updated immediately on install so I guess it is the latest release.

There is no account or Airsync.

It just appears that eM Client does everything in the foreground and hogs all of my computer resources.

As with this morning and the emptying trash, why can that not happen in the background and allow the user to carry on with using eM Client without it monopolising the computer resources.

When clicking on an email why does it take sooooo long for the preview to show even if it has downloaded the email initially, and downloading an attachment is unbearably slow can there be, or is there, a setting to download all attachments immediately.

Additionally can eM Client download the full message including attachments in the background and then alert the user to a new message once downloaded rather than alerting them to the message first and then the user having to wait for it to download.

This should apply to IMAP & POP3.

Thanks for listening.

Version 6.0.20990.0

***** UPDATE *****

I deleted the two accounts I brought over from Outlook and everything is much faster with only the two IMAP accounts.
I will do more testing to try and narrow down the issue and report back.

I take it all back it was fast for 5 minutes now it has totally stoppped even saying I am not connected to server, I definitely am and now is slower than a wet week…

Hi Grant, can you please try to update your application to this version: and check if the issue persists?

Thank you,

Hi Paul,

I have downloaded and installed the above file, it makes no difference.
I note that I have two mail files, one called “mail_data.dat” and another called “mail_fti.dat”.
The first one has a size of 100Gb the other 1.5 Gb.
I logged into my gmail account and it is only 1.5Gb which is the same as the latter but it still wants to download the messages each time I preview, why is that if it is on my hard drive it should be instantaneous.
I have no idea what the 100 Gb file is as my outlook PST file that I initially copied over was only 5 Gb.
I will do more testing throughout the day as I can and let you know if anything fixes it.

More testing has suggested that the 100Gb file was to blame I uninstalled the software deleted all files relating to it in my user profile and reinstalled using only the IMAP accounts not the Outlook Pop3 accounts and it is running fast.
Can you please confirm whether there is a bug in the importing from Outlook.
Process used initially was;
File --> import --> import from outlook --> import whole account (files, folders & settings).
This is what created the 100Gb file I think,

Hi Grant we have not had any reports of large files being created by outlook import. However the files you’ve mentioned are your database files that contain your email data. If you were using a POP3 account, all your data were stored locally, so if you’re receiving a large number of emails the files may get larger, however 100GB seems a bit too much.

IMAP should synchronize all your data between your client and the server and what you have available on the server will be available in eM client, hopefully using these accounts you won’t encounter these kind of issues again, but if you do, please let me know. Or possibly download this utility and run the utility when you notice any performance issues.

The tool will create a stack dump file containing more information about the application’s processes. If you come across these issues again, send me this file to with a reference link to this topic.

Thank you,

I have tested over the past few days and all is fine, it was that large file.
When I imported from Outlook a second time I noticed that eM Client registered about 75 or more PST files for outlook, there definitely was only two so not sure what it was looking at.
I unticked each one individually (a group option would be a good idea, or default to untick and then let user tick on) and imported only the two I wanted.
All is good and I’m liking the features so far.

Hi Grant, glad everything is working as expected, please make sure to let us know if you come across any further issues or question, we’ll be happy to help.

Thank you,