Database size issue


My emClient is taking up a lot of disk space (20GB!).

When I ran CCleaner, I saw this -

Can I delete one of those to save space? Which one? dat-bak or dat?

Any ideas on how to help reduce the amount of space it takes? I use IMAP.


The bak files are created when eM Client does a database repair after an incorrect shutdown or some other database error. These files are not needed for normal use.

What you can do is close eM Client and run C:\Program Files (x86)\eM Client\DbRepair.exe to check that everything is fixed, then open eM Client and make a backup, just in case. The backup can be done in Menu > File > Backup. Then after closing eM Client again, delete the bak files. Actually, restoring the backup will remove the bak files also and clean up the database, so that might be an easier and quicker option. That will reduce the database size to almost half.

Using IMAP with downloading messages for offline use not selected, will result in a fairly small database. That is because the message bodies will stored on the server rather than on your computer. There are some disadvantages to that as when there is no Internet connection you will not be able to view the message body, and it may take a second or two to open large messages when you click on them. The setting can be changed in Menu > Tools > Accounts, then in the Synchronization section of the IMAP tab. I am not sure if this will reduce the database size if the offline data has already been downloaded, but it will not grow much afterwards…

Thanks Gary - I went to do a backup and received this message -

But when I went to exit emClient, I received this message -

What should I do?


Also, how will can I check to see if a backup is complete?

I just received this error too even though C:\Program Files (x86)\eM Client\DbRepair.exe  showed no errors -

The backup may take some time, so let it finish. Once it is done and you do a restore, eM Client will need to close. That is normal.

If you are not using the latest version of eM Client, you may want to download it from

During the backup, you will see an indicator of the progress:

Afterwards you can also check in the log: