delete(cache.iamGroupsMap, group)
		cache.iamGroupPolicyMap.Delete(group)

		cache.updatedAt = time.Now()
		return nil
	}

	gi := cache.iamGroupsMap[group]

	// Updating the group memberships cache happens in two steps:
	//
	// 1. Remove the group from each user's list of memberships.
	// 2. Add the group to each member's list of memberships.
	//

		return
	}

	user, exists := globalIAMSys.GetUser(ctx, accessKey)
	if exists && (user.Credentials.IsTemp() || user.Credentials.IsServiceAccount()) {
		// Updating STS credential is not allowed, and this API does not
		// support updating service accounts.
		writeErrorResponseJSON(ctx, w, errorCodes.ToAPIErr(ErrAddUserInvalidArgument), r.URL)
		return
	}