I have pickpocket level 60. When I tried to steal my 2000 gold back from Vipir the Fleet after, ironically, he was training me to pickpocket, there was a 0% success chance. Other items in his inventory all had a 90% chance due to my skill level, but the gold was not accessible. Any ideas what made it this way?
Specifically for gold there is an unknown formula for maximum gold value that can be pick-pocketed based on the level of the character's Pickpocket skill and which perks they have. This can result in situations where even a small change in gold value can result in huge swings in percentage chance of success.
2000 gold is a lot of gold, it's going to be pretty hard to steal it back unless...
One way to completely 100% guarantee a successful pickpocket attempt is to paralyze the target first. As soon as the victim begins to get back up, try to pickpocket them and you will be able to take anything no matter the percentage chance displayed.
It is good to note that if you pickpocket this way your level will not increase.
Though on another website they seem to have the formulas for chance to steal on stealing items and gold
Base_chance_formula = ( ActorSkillBase + Player_skill ) × ActorSkillMult + ( TargetSkillBase + NPC_skill ) × TargetSkillMult - Detected
Stealing Gold or Single Item: ( Base_chance - Gold_amount / 10 - 4 × Item_weight + Sneak_bonus ) × Effects_mult + Light_Fingers + Night_Thief + (Cutpurse if Gold)