Just wanted to post this problem so that it can be fixed in future version(s). The sooner the better.
Yesterday I have upgraded my Windows 10 OS to the latest build number (1709) and after the upgrade, eM Client stopped working. Stopped working in the sense that all my email accounts were not connecting. After a lot of re-installations and cleaning the profiles and registry I found this forum post that really helped:
The problem came form the antivirus program. Somehow it was blocking eM Client to connect to the hosting provider (Gmail). After disabling those port protocols (583,993) in the antivirus everything stared working great. The problem was not here using the old Windows build.
Windows 10 b1709
Eset Antivirus 10.1.235.0
eM Client 7.0.26453.0 (Also tried with the latest and still didn’t worked)
Let me know of any questions you might have. I can also provide screenshoots.