I archived my old email from the mail folder that time. I would like to open my old emails now but the most recent version on eMClient doesn’t seem to be able to read those emails.
Here is what I did:
I installed the most recent version of eMClient
relocated the mail folder into a new empty folder
restarted eMClient so that it learns the new location of the emails
exited emclient
emptied the folder
copied all the old files into the folder
started emclient
It doesn’t show my emails.
then I exited again
kept all the files
copied the old files and overwrote the colliding ones
The current version of eM Client, 7.x, can only import from version 6 database. If that is what you used (version 6 was released at the end of 2013) then once you have copied the old database to the appdata directory as you described above, open eM Client and go to Menu > File > Import > eM Client 6.
You can backup your current version 7 database using Menu > File > Backup, and then uninstall version 7 and delete the database directory when asked.
Download and install the last version 5 from the Release History, then close eM Client and copy your old files as you did before. Restart eM Client 5 and export any messages you want to keep. You can use Menu > File > Export > Export messages to .eml. You can select multiple folders also which is quite useful.
When that is done close eM Client and re-install version 7. Restore the backup you just made, and finally import the version 5 messages you just exported.