All eM Client files *.dat-bak after recent purge

After a recent purge, most of the files in AppData\Roaming\eM Client are *.dat-bak, dated 12/24/17, and the size and date of the file never changes. 

The following files on the same page are dated 7/3/18 (the date of the purge): accounts, categories, certificates, main, rules, settings, snippets, templates, widgets, and have both *.dat and *.dat-bak files. 

There is another folder (c25a669d-36f2-9452bc…) at the top of the list of files, just under the Archive folder, which contains both *.dat and *.dat-bak files for folders, mail, mail_fti, and mail_index, all dated 7/3/18, which appear to be serving the purged message storage and new incoming and outgoing messages.

My problem and/or question is this:  eM Client was taking a long time to load, which is why I purged the messages.  These are stored in off-line archive files, NOT the eM Client Archive.  Is it possible to delete the *.dat-bak files for folders, mail, mail_fti and mail_index, and replace them with the *.dat and *.dat-bak files in the c25a669d… folder?  Or should I just uninstall eM Client and start over again?

I would sincerely appreciate any help – I like to keep my machine squeaky clean, and this is really puzzling …

The c25a669d-36f2-9452bc… folder is the cached store for your email account. It is best not to delete or alter any files in the database directory as this could break the SQLIte database. However . . . 

Sometimes these bak files are created during crash or database check. You can close eM Client and run C:\Program Files (x86)\eM Client\DbRepair.exe. That will ensure that the database in OK, then you can manually delete them if they are still there afterwards. eM Client needs to be closed to delete the files.
One way to keep eM Client squeaky clean is to delete the database and start again. Uninstalling the application will not delete the data. If you have any data in Local Folders, you want to export or move it to online folders first as this will completely remove any data on the computer.

To delete the database, close eM Client, and then delete or rename C:\Users[username]\AppData\Roaming\eM Client. You may have to show hidden items in Explorer to do that. When you restart you will need to setup your email account again, after which eM Client will sync with the server.

Unfortunately deleting the database also removes any settings, templates, signatures etc., but you can export those in Menu > File > Export > Export settings to .xml if you need to keep them.

After deleting the database and restarting, you can import these settings through Menu > File > Import > eM Client settings (.xml)

Thank you sooo much for your response and advice, Gary.  You are so right about the crash – Windows 7 crashed and burned in late May, and I have spent most of June trying to get used to Windows 8.1 (and make it work like Win7).  I also did a database check  on July 3 after the purge, and it is not corrupted.  I will run DbRepair again before I do anything further, just to be on the safe side.

If, by “Local Folders” you are referring to the folders under the main (Inbox, Oubox, etc) folders in the left-hand column, they are empty.  Since I started using eM Client I have created a new folder called “Active” under the main folders, where I store all messages in categories for the current year.  At the end of the year, I use “save as” (which saves the actual send or receive dates) to move those files to off-line storage, then delete the Active folder and create a new one for the ensuing year.  Would it be better to use the Local Folders for this?

Yes, if you are going to delete the database, you want to save that Archive folder first. Anything in those Local Folders will be deleted. The same with calendar and contacts that are not synced with the server. If in doubt, always make a backup (Menu > File > Backup) before deleting the database. Or if you just rename the database folder, you can always rename it back at a later time.

There are some different ideas about archiving. Some believe that the archive should be on the server, and there have been extensive conversations about that on this forum. But the concept used in eM Client for automatic archiving is to remove the messages from the server and store them in Local Folders as this reduces the space used on the server. Storing historical emails outside of the application, as you are doing, is also a common practice, and because the files are eml, they can be opened by most other email clients as well. I think you just need to find what works best for you.