Just updated to v8 and getting constant errors with Exchange 2010.
I currently have 40 of these errors… in the last 4 minutes:
[Exchange Web Services] Synchronizing folder list failed due to the following error: Property is not valid for this object type.
what the heck is this?
This is getting ridiculous. The stupid error window pops up with EVERY action now. Really thinking of downgrading to 7.
Anyone have the latest v7 installer?
So I figured I’d give it another go as we’re up to v8.1. Installed on a different machine, and it wouldn’t load anything at all. It could SEND mail, but couldn’t show any folders.
Error message was:
[Exchange Web Services]Synchronizing folder list failed due to the following error: Property is not valid for this object type.
Back to v7
Who is the email provider?
Me. My own exchange server.
If it was maintained by an email provider or company, I would have suggested you get on their case because the server is not properly configured, and that is why version 8.x of eM Client is not happy. As it is you who maintains it, I won’t suggest that . . . 
I have been testing 8.1 and previews of 8.2 with Microsoft maintained Exchange servers and am not finding any issues, so it might be something in your particular server settings that is not compatible with the latest releases of eM Client. You did not say what version of 8.1 you tried but I assume it is the latest.
If you have a Pro License, I suggest you open a support ticket with eM Client. They will be able to interpret the logs and advise you further as to the cause.
I don’t have a pro license at the moment… I originally started using it because I wanted to keep work/personal email separate on my work machine (and outlook is for work).
Yes it was latest version (downloaded this morning).
It may very well be something in the server config, but v7 and every version of outlook I’ve tried works perfectly (as well as various mobile clients - both apple and android).