Install the extension with a ZXP installer
Step 2 of 5. After Effects cannot open a .zxp on its own. Adobe retired
Extension Manager and never replaced it, so a free ZXP installer does the job.
You need it once.
Quit After Effects before you install
After Effects reads its extensions folder at launch. Install while it is running and the panel will not appear, which looks exactly like a failed install.
.zxp on its own. Download the free ZXP/UXP Installer from aescripts, for macOS or Windows, and open it.Drag the file you downloaded in step one onto the installer window. It tells you when it succeeds. On macOS it installs into your user Library and on Windows into AppData, and it handles both without asking.
The installer lists what it has installed. After Effects MCP should appear with its version and the After Effects releases it supports.
Go to Window ▸ Extensions ▸ After Effects MCP. The panel opens as a dockable window, so put it wherever suits your workspace.
If it does not work
| What you see | What it usually means |
|---|---|
| The panel is not in the Extensions menu | After Effects was running during the install. Quit it fully and reopen |
| The installer reports a failure | The file was unpacked by your browser and is no longer a .zxp. Download it again |
| The menu shows Extensions but the list is empty | See the unsigned-extension note below |
| The panel opens blank or grey | Close and reopen it once. If it persists, see Prism cannot reach After Effects |
If the panel still does not appear
Most people never need this. It applies only to an unsigned build, which some installs will not show until you turn on a system setting for unsigned CEP extensions.
| Platform | What to set |
|---|---|
| macOS | PlayerDebugMode = 1 in ~/Library/Preferences/com.adobe.CSXS.12.plist |
| Windows | PlayerDebugMode string value 1 under HKEY_CURRENT_USER\Software\Adobe\CSXS.12 |
Restart After Effects and check the menu again. This is a one-time switch. If it is unfamiliar, ask your IT team or email support@oneprism.io.
Common questions
Download
Step one of five: download the After Effects MCP extension from your Prism dashboard. One .zxp file, every plan including Free, nothing to unzip.
Sign in
Step three of five: open the Prism panel from Window then Extensions, click Sign in, and finish in your browser. No key to copy, no password typed into AE.