After Effects MCP install errors and panel states

This page covers everything between the download and the panel running After Effects' script: the panel missing from the menu, a blank panel, and the host states and install advisories the panel shows when it is open but nothing runs. First move: quit After Effects fully and reopen it.

Where the panel lives

Adobe extensions can be installed for you alone or for every user on the machine. Prism must be in yours: in the machine-wide location its files are owned by the system account, and After Effects, running as you, cannot read them.

The ZXP/UXP Installer uses the correct column by default. Two copies are tolerated (a beta and a release build); a third is a blocker.

The panel does not appear

Not in Window ▸ Extensions

What it means. After Effects reads its extensions folder once, at launch, so a panel installed while it was running is invisible until the next launch.

Do this.

1. Quit After Effects fully: Cmd+Q on a Mac, close the application on Windows. Closing the window or the panel is not enough.
2. Reopen it and look again under Window ▸ Extensions ▸ After Effects MCP.
3. On After Effects 2024 the panel must be version 1.4 or later; earlier builds are dropped silently, with no message. Download the current build from your dashboard.

Shows in: nowhere; the entry is simply absent.

Unsigned build · install-unsigned

You see: "This is an unsigned build. After Effects drops it whenever PlayerDebugMode resets. Install the signed .zxp instead."

Meaning. This copy of Prism is unsigned, so After Effects can drop it at any restart.

Fix. Install the signed .zxp from your dashboard, then quit and reopen After Effects.

Shows in: the panel banner, or an empty Extensions menu.

The panel opens blank or grey

What it means. The panel's stylesheet did not load.

Do this. Close the panel and open it again once. If it stays blank, reinstall the current build for your account and restart After Effects.

Receipt download is out of date

What it means. The download attached to your purchase receipt serves an older build than the one the server runs, so the panel shows "Please update to v{version}" the moment it opens.

Do this. Download the panel from your dashboard, which always serves the current build, and install it. Quit and reopen After Effects. If the panel then reports a duplicate, delete the path it names.

Your antivirus quarantines the panel

What it means. The current panel opens links through a Windows system helper and fetches an analytics script at runtime, which some scanners flag. Both are removed in the next panel release.

Do this. Allow After Effects in your firewall or antivirus, reinstall the current build for your account, then quit and reopen After Effects.

Host states: the panel is open and every request fails

The panel measures the cause rather than guessing it: whether the script file exists, whether your account can read it, whether After Effects loaded it, whether the loaded copy matches the panel's version, and whether After Effects is running scripts at all. A live answer from After Effects outranks anything on disk. Your AI client sees the state as the error code; the panel shows it as a banner with a Reinstall, Re-check or Copy button, and when it clears reads "After Effects can run Prism."

Install not readable · host-not-readable

You see: "After Effects cannot read Prism's script file, installed system-wide under another account. Reinstall Prism for your account."

Meaning. After Effects cannot read Prism's files because they belong to another user account. Nothing ran.

Fix. Reinstall Prism for your own user account, then quit and reopen After Effects.

Shows in: both.

Install missing · host-missing

You see: "Prism's script file is missing. Reinstall Prism, then restart After Effects."

Meaning. Prism's files are not on this machine. Nothing ran.

Fix. Reinstall Prism, then quit and reopen After Effects.

Do not reinstall repeatedly on a Windows panel older than 1.4. Those builds reported this state falsely while the script was loaded. Update to the current build instead.

Shows in: both.

Panel not loaded · host-not-loaded

You see: "Prism's script did not load. This is the install, not an open dialog. Reinstall Prism to {userDir}, then restart After Effects."

Meaning. Prism is installed but After Effects did not load it. Nothing ran.

Fix. Reinstall Prism for your user, then quit and reopen After Effects.

Shows in: both.

Old version loaded · host-stale

You see: "After Effects still has an older Prism script loaded. Restart After Effects."

Meaning. After Effects is still running an older Prism than this panel. Nothing ran.

Fix. Quit and reopen After Effects. Do not reinstall.

Shows in: both.

Results not returned · host-result-lost

You see: "Prism runs, but its results are not reaching the panel. Your install is fine, so do not reinstall. Restart After Effects. If it repeats, email support@oneprism.io the code below."

Meaning. After Effects ran the work, but its result did not come back. The project may have changed.

Fix. Quit and reopen After Effects. Do not reinstall; the install is fine.

Shows in: both.

After Effects busy · engine-unreachable

You see: "After Effects is not running scripts, usually because a dialog is open or a render is going. Dismiss any dialog, then re-check."

Meaning. After Effects is not running scripts, usually because a dialog or render is open. Nothing ran.

Fix. Close any open dialog in After Effects, wait for renders, then press Re-check.

After two silent replies in a row the header also shows "After Effects is not responding to Prism. Close any open dialog, check your other monitors, then restart After Effects."

Shows in: both.

Panel not attached · cep-unavailable

You see: "After Effects did not give this panel its extension bridge. Reinstall the signed .zxp, then restart After Effects. This copy is unpacked, so it also needs PlayerDebugMode 1."

Meaning. After Effects opened the panel without the link it needs to run anything. Nothing ran.

Fix. Reinstall the signed .zxp, then quit and reopen After Effects.

Shows in: the panel banner.

Cause unknown

You see: "Prism cannot tell why After Effects is not responding. The details are recorded. Restart After Effects."

Meaning. After Effects is not responding and Prism cannot tell why. Nothing ran. The details are recorded.

Fix. Quit and reopen After Effects. If it repeats, copy the diagnostic and email support@oneprism.io.

Shows in: the panel banner.

Call not answered · jsx-engine-unavailable

You see: "After Effects' script engine did not respond (empty reply)…"

Meaning. After Effects gave no reply to this call, so nothing ran. Prism is checking why.

Fix. Close any dialog in After Effects. If it repeats, quit and reopen it.

Shows in: your AI client.

Install advisories

These do not stop Prism today. They will break the next update, or lose you a snapshot. All of them show in the panel banner, the first one as "{advisory} ({n} more install problem(s) — see the log.)", with a Re-check button.

Extra copies installed · install-conflict

You see: "Prism is installed {total} times, so After Effects may load the wrong one. Delete the extras, then restart After Effects: {paths}"

Meaning. Prism is installed more than once, so After Effects may load the wrong copy.

Fix. Quit After Effects, delete the extra folders listed below, then reopen. Do not reinstall.

Installed in wrong folder · install-path-unrecognized

You see: "Prism is installed outside the extensions folder, so the next update will add a second copy. Reinstall to {userRoot}, then delete {dir}."

Meaning. Prism is installed outside the extensions folder, so the next update will add a second copy.

Fix. Reinstall to ${userRoot}, then delete the old folder.

Install folder locked · install-dir-readonly

You see: "You cannot write to Prism's install folder, so updates will fail. Reinstall for your account only. No administrator needed."

Meaning. You cannot write to Prism's install folder, so updates will fail. Everything else works.

Fix. Reinstall Prism for your account only. No administrator needed.

User folder blocked · install-user-dir-blocked

You see: "Your account cannot write to the per-user extensions folder, so the normal install cannot run here. Ask IT to allow {userRoot}, or to install Prism as administrator."

Meaning. Your account cannot write to its own extensions folder, so the normal install cannot run here.

Fix. Ask IT to allow ${userRoot}, or to install Prism as administrator.

Synced profile · appdata-redirected

You see: "Prism sits in a synced or network profile, which After Effects often cannot load extensions from. Ask IT for a local AppData path, or install as administrator."

Meaning. Prism sits in a synced or network profile, which After Effects often cannot load from.

Fix. Ask IT for a local AppData path, or install Prism as administrator.

Panel opened incomplete · node-unavailable

You see: "After Effects started this panel without Node access, so Prism cannot check its install or read its log. Reinstall the signed .zxp and restart After Effects. If it repeats, email support@oneprism.io."

Meaning. After Effects opened the panel incomplete, so Prism cannot check its install or read its log.

Fix. Reinstall the signed .zxp, then quit and reopen After Effects. If it repeats, email support@oneprism.io.

File saving off · script-write-blocked

You see: "After Effects blocks scripts from writing files, so Prism cannot save snapshots or its log. Turn it on below, or in Preferences, Scripting and Expressions."

Meaning. After Effects blocks scripts from saving files, so Prism cannot save snapshots or its log.

Fix. Press Turn it on, or enable it under Preferences ▸ Scripting and Expressions.

Still stuck

If you have reinstalled for your account, removed any duplicate the banner named, quit and reopened After Effects, and requests still fail, email support@oneprism.io with the panel version from the footer ("After Effects MCP v…") and the Copy diagnostic from the panel's Support section. On panel 1.5.1 that section may be empty; the version plus the state name is enough.

Other panel states

Setting not changed · pref-fail

You see: "Prism could not set that preference here. In After Effects o…"

Meaning. Prism could not turn on file saving for scripts. Snapshots and the log stay off.

Fix. Turn on Allow Scripts to Write Files and Access Network under Preferences ▸ Scripting and Expressions.

Result not readable · result-file-unreadable

You see: "The result was too large to cross After Effects' scripting b…"

Meaning. The work ran, but its result was too large to hand back and could not be read from disk.

Fix. Run it again asking for less data at once, for example fewer items or fields.

Panel not listed · panel-not-listed

You see: "(no text today)…"

Meaning. After Effects does not list Prism. It reads new installs only at launch.

Fix. Quit After Effects fully (Cmd+Q), then reopen. After Effects 2024 needs panel 1.4+.

Download out of date · download-outdated

You see: "Please update to v${serverVer}…"

Meaning. The download in your purchase receipt is an older panel than the current release.

Fix. Download the current panel from your dashboard instead.

Blocked by antivirus · panel-quarantined

You see: "(no text today)…"

Meaning. Your antivirus removed or blocked the panel. Nothing ran.

Fix. Restore it in the antivirus, download the current build, reinstall, then relaunch After Effects.

Common questions

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