@maboleth
On which platform and megaserver do you play TESO? ZOS must know that before they can investigate your report: Guidelines for Bug Report Forum. If you do not follow the guidlines, then ZOs ordinarily ignores your OP. (I am just another player, not an agent of ZOS.)

maboleth wrote: »

This NPC doesn't talk anymore nor wants to open his mouth at all. He worked perfectly before Summerset update.

Whatever you did to the base game, you messed up some stuff that worked normally.

Yah, when they develop another "Chapter" and/or Update to introduce new features to the Base Game, the ZOS developers have an manifest tendency to break things that were working. Sometimes they also introduce errors when they change features that did not need to be changed. Fixing this error will probably not be among their highest priorities, so please don't hold your breath.

FWIW, I intend to see whether the software behaves the way that you have reported. The most direct way to report a bug is to:

• Take a screenshot, if appropriate.
• Press the <F1> key to access the Help menu, or enter the command /bug in the text entry field of the Chat Window.
• Select Feedback and proceed from there. Report this either under the category "Interactibles/lockpicking" or the category "Audio".

That said, I don't suppose a screenshot is needed unless the software displays a blank dialogue when you attempt to interact with the stablemaster. (Be sure that the character is the stablemaster!) If you attempt to see the mounts available for sale and the software displays anything, then capture that in a screenshot. Check the box at the bottom of the report to submit a screenshot. It will automatically attach the most recent screenshot created and stored in the ...\Elder Scrolls\live\Screenshots folder.

Have fun!