How do I fix the arcane blacksmith glitch?

Solution 1:

Some suggestions based on the article on the Thieves Guild Master armor:

http://elderscrolls.wikia.com/wiki/Guild_Master%27s_Armor_Set

  1. Make sure you have leather to upgrade them;
  2. Make sure you're at skill 100, because they're not affected by the perk that reduces the skill requirement for improving armor.
  3. Make sure you're using the set you acquired as a quest reward, because sets acquired through pickpocketing and maybe spawning a set in cannot be upgraded.