Your magicka usually stops regenerating in Oblivion for a specific in‑game reason, a disease/curse, or a bug. Here are the most common causes and fixes.

1. Check your birthsign first

Some birthsigns disable natural magicka regen by design :

  • Atronach birthsign: You get a huge magicka pool and Spell Absorption, but your magicka does not regenerate over time at all.
  • If you picked Atronach, this is not a bug.
    • You must refill magicka with:
      • Potions of sorcery or restore magicka
      • Ayleid wells
      • Spell Absorption (letting hostile spells hit you)

Quick check:
Pause → Character menu → bottom of the screen shows your birthsign. If it’s Atronach, that’s your answer.

2. Look for diseases or negative effects

A very common reason is a disease or effect that stops or cripples magicka regen.

  • Open the Active Effects tab in your magic menu and look for:
    • “Damage Magicka” or “Drain Magicka” effects
    • Diseases like Astral Vapors (from will-o-the-wisps etc.) that reduce or block regen.
  • If you see one of these:
    • Drink a Cure Disease potion
    • Pray at a chapel altar in any major city
    • Wait or sleep 24 in‑game hours and check again

Players report that curing the disease and then praying at a shrine (and sometimes saving/reloading) makes magicka regen start working again.

3. Make sure it’s not “normal” slow regen

Oblivion’s magicka regeneration is tied to Willpower and actors’ stats , and early characters often feel like it’s “not regenerating” when it’s just extremely slow.

  • If your Willpower is low and you don’t have Fortify Magicka/Willpower gear, regen can feel almost nonexistent.
  • Wait a full in‑game hour and see if the bar moves at all. If it does, it’s working, just slowly.

4. Check for partial regen (stops before full)

Sometimes magicka:

  • Regenerates only up to a certain fraction (like 85/100) and then stops.
  • This can come from:
    • Permanent or long‑lasting Damage Magicka effect that lowered your maximum magicka. The UI can be confusing: the “100” you remember might be outdated, but your actual max is now lower.
* Modded effects that cap your magicka.

Try:

  • Drinking Restore Magicka / Restore Intelligence potions.
  • Using a stat restoration altar or spell.
  • Temporarily unequipping all gear, waiting an hour, and seeing what your bar settles at.

5. Mods and bugs

If you play with mods (especially “remastered” packs or spell/attribute overhauls), there are known situations where magicka regeneration breaks :

  • A mod that adds “toggle” spells can leave a hidden effect active, preventing regen until you re-enable the mod and untoggle/reset the spell.
  • Enchanting glitches or spell exploits can sometimes cause odd magicka behavior that “fixes itself” only after certain actions like saving, reloading, or changing an enchantment.

Try this sequence:

  1. Save your game to a new slot.
  2. Fully exit to main menu, then reload.
  3. Pray at a chapel altar.
  4. If you use mods:
    • Temporarily disable any “toggle spell” or magicka/needs overhauls.
    • Load, check magicka behavior, then re‑enable and test.

Several players report that saving, reloading, then using a shrine finally made their magicka start regenerating again after a bug.

6. Quick checklist you can follow

  1. Check: Is your birthsign Atronach?
    • Yes → It’s working as designed, use potions/Ayleid wells/absorption to refill.
  2. Open Active Effects: Any disease or “Damage/Drain Magicka”?
    • Yes → Cure Disease potion + chapel altar + wait/sleep.
  3. Still not working?
    • Save → quit to main menu → reload → pray at shrine again.
  4. Using mods?
    • Disable magicka/spell toggle mods, load, test, then re‑enable.
  5. If magicka only refills partway:
    • Look for permanent Damage Magicka, Restore your stats, unequip gear and recheck your actual max.

TL;DR: The two big culprits are the Atronach birthsign (no regen by design) and hidden diseases or effects like Astral Vapors that block magicka regeneration until you cure them and sometimes reload/pray at a shrine.

Information gathered from public forums or data available on the internet and portrayed here.