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Error / Warning

Error 21::31 — "preferences file is not valid"

The error

"preferences file is not valid (21::31)" on launch — usually follows an abrupt shutdown of AE.

Why this happens

The Prefs.txt settings database was corrupted, typically by AE being force-quit or the OS crashing mid-write to it.

How to fix it

1. Hold Ctrl+Alt+Shift (Win) / Cmd+Opt+Shift (Mac) while launching to generate a fresh preferences file.
2. Re-apply your custom workspace/settings afterward — the reset wipes them.

Source: Extended Error Database · error 21::31 "preferences file is not valid"

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