Database file doesn't reduce on deleting messages AND emptying trash

I’m migrating to your eM Client from Eudora. I am preparing for a larger move with more accounts, but have identified some problems I hope you can address.
1st: I imported about 6 GB of my prior email files into my local folders (I prefer POP account). I checked and was happy with the import, but then deleted the files and emptied the trash multiple times, but when I look in the eM Mail client data folder (/user/AppData/Roaming/eM Client) I still find a 6+ GB mail_data.dat file. This is disconcerting, as it leads me to believe the mailbox contains a lot of information that I don’t want kept. Can you confirm how I can truly empty the data file?
2nd: I’ve noticed the eM Mail client hangs a few seconds unexpectedly for simple tasks like composing or sending an email from my pop account. In addition to this POP outlook account, I also have an IMAP gmail account set up. Any explanation for the long waits? Would the large mail_data.dat file for emails stored in local folders slow it down? Is this delay to be expected and accepted?
3rd: Is there any ability to set different sync frequencies for each mail account? Specifically I don’t want the seemingly slower IMAP gmail sync to retard everything else when this account is rarely used. Is it possible to just sync my gmail contacts and calendar, and neglect the mail, and would that improve performance?
I have been reading the web documentation to better understand the software, and I thank you very much for your support. Thank you :slight_smile:

Hello, eM Client reduces it’s database size on application startup, to keep running fast while you remove the data. After removing some of the data may remain in the database and are cleared once the database is being reduced on startup, however this doesn’t occur on each application startup.

You can speed up the process by running this utility, which will remove all the unwanted data from your database structure.


Thank you for this tool. It has solved my excessive database size issue. Excellent mail app!

Is there any way to block the gmail “All Mail” folder from downloading in IMAP mode? 

Hi, glad it works. You should be able to disable the All Mail folder from synchronising with the IMAP connections in your gmail account settings.


I was able to select what IMAP folders I want to sync in gmail webmail settings. Most excellent, Thank you!

I tack new questions to this post as they relate to my imported mail.

From Eudora I used Aid4Mail to export my mail as .eml files. Overall I’m happy with this, as it seems to have generated the majority of my mail with proper attachments, and eM Client seemingly got everything imported.

I face several issues with uncertain causes I now ask about:

 - Many (but still only a few % of total) messages were empty and/or missing most info on to/from/date/subject. Some of these messages had some partial content, but many have nothing, which raises concerns that the message is now lost. I expect to just delete these, and clearly it may be a problem from Aid4Mail, but I wonder if you have any experience with this? Are these likely lost messages, or extra incomplete copies? 

 - Is there any way to preserve the read/unread/replied/forwarded status of messages? Should I use a different email export/import stadard than .eml files to do this?

 - Is .eml the best and most future proof method of backing up ones email?

Thank you very much in advance. I’m very happy with eM Client!

Hello, .eml is a standard format for email messages, however it’s not possible to keep the flags in an exported message, as flags are handled by the server. New message received by the server is automatically marked as unread.

I’m not quite sure about the empty messages, it can be a corrupt message that the exporter couldn’t handle or just a “ghost” message, from something leftover in your previous database. It’s hard to say without an example - but if some of the messages have partial content, I’m afraid these might be corrupt.