I have recently installed Em client to windows 10.
Since then I am having problems with the text size 
Some email is OK. Others really small like this image.
Also another email viewed on windows 7 and windows 10
Can someone help please 
Hi Robert,
do the emails with small font arrive from certain email addresses only? Or is it completely random? We had this issue previously with iCloud email senders.
Regards,
Olivia
very random
Hi Robert,
it’s hard to pinpoint this issue since it seems to have no definite source. The issue could also be with the current versions IE core or the User Interface which isn’t quite ready for larger DPI monitors and not quite ideal for windows 10. I believe this problem will cease with the next version of eM Client, which got rid of the IE core and the UI was completely remastered.
As a workaround for now, I can suggest trying to set a default font size to something bigger for reading emails and to view emails as Plain text by default (both available in Tools > Settings > Mail >Read section).
Regards,
Olivia