Plugin Formats: VST2, VST3, Audio Units and AAX.

Buying a plugin is half the journey: the other half is getting your DAW to recognise it. Between those two points is vocabulary worth mastering—VST2, VST3, Audio Units and AAX—and four typical failures: the wrong format, the wrong folder, the wrong architecture and an inactive licence.

This guide explains each format, who uses it and why, then covers plugin scanning: the process by which the DAW discovers installed plugins and the actual cause of most “my plugin does not appear” problems. If you have just installed the program and still need that first hour of audio setup, the groundwork—drivers, device, buffer and sample rate—is in Installing a DAW: Drivers, Audio Device, Buffer and Sample Rate.

Which Format Fits Each System

A plugin format is the contract between the program processing audio and the plugin doing it: it defines communication, parameter exposure and interface delivery. Four coexist in practice today:

• VST2, Steinberg’s historical format, present in almost all Windows and macOS hosts.
• VST3, its successor, with better handling of state, inputs and outputs, and idle consumption.
• Audio Units, Apple’s technology that exists only on Mac.
• AAX, Pro Tools’ own format and ecosystem.

The following table turns “which format do I need?” into a specific answer for your system and DAW; per-program installation steps are in How to Install Plugins in Ableton, FL Studio and Logic.

VST2 and VST3: The Common Format

If you work on Windows, VST is your world: almost all manufacturers publish in VST2 and, increasingly, VST3 too. The same happens on Mac, except many plugins are released as both VST and Audio Units.

VST2 is a single file: .dll on Windows and .vst on macOS. That simplicity is also its problem: there is no installation registry, just a file in a folder, so everything depends on whether that folder is scanned by the DAW.

VST3 installs as a package (on Windows, a directory with the .vst3 extension) and brings practical improvements: when unused, the plugin can shut down completely, consumes zero CPU while idle, supports inputs and outputs the user activates as needed, and saves state more reliably when loading projects. That is why the move from VST2 to VST3 is not a fashion: it reduces actual load in projects with many plugins.

A useful detail when sharing projects between computers: a Mac project using VST pairs with VST on Windows, but an Audio Units project does not find its equivalent on a PC. If you collaborate, prioritise the VST format for your plugins.

Audio Units: Apple’s Format

Audio Units is Apple’s plugin technology, integrated into macOS and used as standard by Logic Pro and GarageBand. It exists only on Mac: there is no Windows version, and no Windows DAW can load it.

Two generations coexist. AUv2 is the classic format, a .component file installed in /Library/Audio/Plug-Ins/Components; AUv3 arrives as an application extension and installs in the applications folder, with the advantage that it can run outside the DAW process. Logic Pro shows both generations in its plugin menus and Plug-in Manager, where each plugin’s compatibility status also appears.

One practical consequence: on Mac, the same plugin can be available as AU and VST. If one does not appear, try the other before reinstalling; often the problem is format, rather than installation.

AAX: Pro Tools’ Own Format

AAX is Avid’s extension for Pro Tools, VENUE and Media Composer. Plugins using this extension have the suffix .aaxplugin and come in two variants: AAX Native, processed by the computer’s CPU, and AAX DSP, processed on HDX system cards and VENUE consoles. Besides real-time operation, AAX allows non-real-time block processing through AudioSuite.

Two consequences to understand before buying:

1. A VST plugin does not work in Pro Tools. If you work in that ecosystem, check that an AAX version exists and is included in the licence.
2. AAX DSP and AAX Native are not interchangeable. A plugin bought for the CPU does not run on an HDX card without the corresponding variant.

Plugin Scanning: Why a Plugin Is Actually Missing

Plugin scanning is the pass the DAW makes at startup—or when you press “rescan”—to walk authorised folders, read each file and catalogue instruments and effects. If a plugin is not in one of those folders, or the file cannot be read, it simply never enters the list.

That is the source of plugins that do not appear: installation is correct, the file is on disk and the menu still does not show it. Five reasons explain almost every case:

1. Folder not enabled. The DAW has default and custom folders; if you installed elsewhere, you must add it.
2. Two formats in one folder. VST2 and VST3 must be separate; mixing them causes scanning errors.
3. Missing companion. On Windows, a VST3 usually includes a .dll in System32 or the system folder placed by the installer; if you manually installed only the package, it may be missing.
4. Wrong architecture. A 32-bit plugin in a 64-bit host, or an Intel plugin without translation on a Mac with Apple’s own chip, will not load.
5. Cached scan. The DAW remembers failures; force a deep rescan. In Live, hold Alt or Option when pressing Rescan; in Logic Pro, use Plug-in Manager to reset and scan again; in FL Studio, use plugin verification with rescanning of already verified plugins.

When scanning fails for a particular plugin, work in this order: check the folder, check the format, force a rescan and only then reinstall.

Apple Silicon, Intel and Rosetta

The transition from Intel Macs to Apple’s own chips added another compatibility layer, because a plugin compiled for Intel is not native on a Mac with Apple silicon.

Three situations coexist in practice:

• Native plugin (ARM). Works directly and is the recommended option for consumption and stability.
• Intel plugin under Rosetta. The DAW can load it if running in translation mode; Apple documents how to open Intel apps with Rosetta, and manufacturers release native updates by version. Installation is the same, but performance and especially stability can suffer.
• Plugin with no compatible version. It will not load, and there is nothing to configure: update or replace it.

Check the manufacturer’s website to see whether the plugin is already native before installing. If an old plugin is essential to your sound, testing it under Rosetta is reasonable; relying on it for an important recording is not.

Licences and iLok: Installed but Not Authorised

Installed does not mean authorised. A plugin may be in the correct folder and still not appear—or appear greyed out—because its licence is inactive.

The three schemes you will encounter:

• Activation in the manufacturer’s account. Enter a code and the licence is linked to your account or a limited number of machines.
• Machine activation. The licence is stored on the computer itself; changing equipment requires deactivation beforehand.
• iLok dongle or session. Some manufacturers require PACE’s iLok platform, with a physical USB dongle or cloud account session. Avid’s official plugin guide dedicates a chapter to this scheme, because it is common in Pro Tools.

Before buying, check the activation and reinstallation policy: how many machines it allows, whether a dongle is needed and whether the licence survives a computer change. It is the difference between a plugin you use and a plugin you own.

Next Step

You now know which format you need and why a plugin may be missing. Next comes the physical step: specific paths by DAW and system, administrator permissions, rescanning and moving large libraries to another drive without breaking anything. All of that is in How to Install Plugins in Ableton, FL Studio and Logic.