How to Enable Complementary Shaders in Minecraft

Downloading and placing the file is only half the job, Complementary Shaders does nothing until you select it in the game's shader menu. This guide covers enabling the pack in both Iris and OptiFine, how to confirm it is genuinely running (not just listed), and what to do when selecting it seems to change nothing.

Enabling in Iris

1. Launch Minecraft on your Iris profile.
2. Open Options → Video Settings → Shader Packs.
3. Find ComplementaryUnbound or ComplementaryReimagined in the list and click it. Iris applies the pack as soon as you select it, the menu itself re-renders with the new lighting, which is your first confirmation.
4. Click Done twice to return, then load a world.

Enabling in OptiFine

1. Launch Minecraft on your OptiFine profile.
2. Open Options → Video Settings → Shaders.
3. Click the pack's name in the list on the left.
4. Click Done. The game reloads its rendering; a short pause is normal.

Confirming the pack is really running

Do not trust the menu alone, confirm in a world, in daylight, near water:

• Shadows: trees and buildings cast soft, directional shadows that move with the sun. Vanilla Minecraft has no shadows like this.
• Water: lakes and rivers reflect the sky and surroundings instead of sitting flat.
• Sky and light: sunrise and sunset carry warm colour; torchlight glows rather than simply brightening blocks.
• The settings screen: reopen the shader menu, the pack should be highlighted as the active selection, and its settings button should open Complementary's own options (profiles, lighting, water). If that screen exists, the pack is loaded.

Selected it, but nothing changed

• You are comparing at night or underground. Shader differences are subtlest there. Test at noon in the open, near water.
• The pack applied but the profile is very light. The Potato profile is deliberately close to vanilla in cost, its look still differs, but raise the profile once to compare, then settle where performance feels right. See the presets guide.
• Another selection overrode it. In OptiFine, "(internal)" means vanilla rendering; in Iris, "Off" disables shaders. Re-select the pack and apply.
• The world did not reload. Rare, but a re-log (leave and rejoin the world) forces a full render reload.

If the pack is not in the list at all

Enabling is impossible until the pack appears. The causes are almost always file placement: the ZIP was extracted, sits in a subfolder or a ZIP-within-a-ZIP, or landed in a different launcher instance's folder. Complementary Shaders not showing in the list works through them in order, and where to put the ZIP confirms the location.

Switching off or switching styles

To return to vanilla rendering, choose "Off" (Iris) or "(internal)"/OFF (OptiFine) in the same menu, nothing is uninstalled. To try the other style, simply select it instead; each style keeps its own settings, as explained in switching between Unbound and Reimagined. Once enabled, a sensible next stop is the best settings guide to move beyond the default profile with intent.

Enabling the pack on a server versus in single-player

Players often hesitate at the multiplayer door, unsure whether enabling shaders is a single-player-only act or something the server must support. It is neither: enabling happens entirely in your own game's menus, and it works identically whether the world you are about to join is local or remote. A shader pack is client-side rendering, it changes how your computer draws the world it receives, and it sends nothing to the server and requires nothing from it. Other players see the ordinary game; only your screen changes. You enable the pack once, from the title screen or the pause menu, and it then applies in every world and server you join until you select a different pack or switch shaders off. Two practical notes follow from this. First, there is no per-world or per-server enabling to repeat, if the pack seems inactive on one server, the cause is on your side (selection, profile, or a reload that did not happen), not the server's. Second, because the choice is purely visual and entirely yours, the polite check is your server's rules page rather than its technical setup: most servers allow client-side graphics, but the rules, not the software, are the authority. Nothing needs to be installed anywhere except the computer you play on.

Choosing a profile at the moment you enable

The moment of first enabling is the right moment to make one deliberate choice: the pack's quality profile. A freshly selected pack runs on its default profile, which is a reasonable middle of the range, but the range itself runs from Potato to Ultra, and the distance between those ends is large in both appearance and cost. Rather than accepting the default blindly and judging the pack by it, open the pack's settings screen straight after enabling (the settings button in the shader menu) and set the profile one step below what you believe your PC can handle. This is not modesty; it is sequencing. A first session that runs smoothly lets you evaluate the look itself, the lighting, water and sky that made you install the pack, while a first session that stutters teaches you nothing except that the profile was too high. Raising the profile later, one step at a time in the same scene, shows you exactly what each step adds and what it costs. Lowering it under pressure, mid-session, after a frustrating hour, teaches neither. Both styles offer the same profile range and both remain fully customisable beyond it, so treat the profile as a starting coordinate rather than a verdict on your hardware. The presets guide explains what changes between levels, and low-end PC settings covers the deliberate low end.

Enabling a second style or a second version

Enabling is a selection, not an installation, which makes trying alternatives trivially easy once more than one pack sits in your shaderpacks folder. If both style ZIPs are present, the list shows both ComplementaryUnbound and ComplementaryReimagined; clicking the other style's name switches the rendering immediately, with the same brief reload as any selection. Nothing is overwritten by switching: each style stores its settings in its own file, so Unbound keeps the profile and options you gave it while you experiment with Reimagined, and switching back restores your earlier setup exactly. The same logic applies to versions. If an older release ZIP and the current one (r5.9.3) are both in the folder, both are listed, and you can select the older entry to compare or to roll back, useful in the session right after an update, before you delete anything. The discipline that makes this work is simply keeping the files: leave both ZIPs in place until you have played enough to know which you prefer, and let the list, not the folder, be where you choose. Removing a pack you might return to means re-downloading and re-placing it; leaving a 0.53 MB file in the folder costs nothing.

Frequently asked questions