I have been using the free version of eM Client the past week or so and have been very happy with the software. However, I just now updated to version 6 on receipt of a notification of the availability of the new version. I am now getting the attached message saying I need a licence. 
Same here
I was having the same program. Go to their website http://www.emclient.com/free-license
you can get a free license. Then copy and paste that to the license option under “Help” tab.
Thanks a lot!
I also found this helpful. I have followed your instructions - now waiting ages whilst ‘this operation might take a while’ How long does this take ?
Excellent, its works.
Thanks
I had the same problem. This procedure allowed me to resolve it. Thanks!
Hello, sorry to see this, but I’m glad you were able to resolve the problem, please note that eM Client after installing it on your computer, only runs in demo mode, in order to use the application further you’re required to obtain a valid license.
Regards,