Since 10130 (slow ring) I am unable to create a message or reply to a message.  Otherwise WLMail appears OK; rules, folders and such.

Pic. 1

Note: This was generated by clicking the [Email Message] on the ribbon.

Pic. 2

When I open a message in a separate window, then click [Reply] Pic. 1 appears, then Pic. 2 after I discard Pic. 1

I am not able to see any errors in Event Log that corresponds to these.

I'm not ready to attempt to repair Essentials just yet.  I hope to get advice here first.