One of the most frequent culprits behind this error is a conflict or incompatibility introduced by third-party scripts, extensions, or UI panels.
Hold down Ctrl+Alt+Shift (Windows) or Command+Option+Shift (Mac) while launching the program. One of the most frequent culprits behind this
Many scripts require specific layers to be selected. One of the most frequent culprits behind this
Navigate to the folder (typically found in Support Files/Scripts/ScriptUI Panels on Windows or Applications/Adobe After Effects/Scripts/ScriptUI Panels on macOS). One of the most frequent culprits behind this
Launch the software. If the error disappears, re-introduce your scripts one by one to find the culprit. Wipe the User Presets Directory