I'm currently using After Effects 17.0.5 and I've probably ran through a bug that won't fix by itself.
It happened when I opened an aep. file that a friend of mine sent me, I was going to check the expressions he used for some animations and when I attempted to change it the editor was shown as a huge text block with no letters. I decided to close the project and create a new one (after closing After Effects completely) and the problem was still there. I checked in "Preferences" > "Scripting & Expressions" and found out this is definetily something like a bug, nothing seems to be changed and the example expression editor box looks like this.
And the program also crashed when I clicked in the Expression Editor from the Preferences window.
Is this a common problem? And how could I fix it without having to download a previous version?
Without a screenshot of the actual expression code and critical info like your system, language settings, what expression engine is used and so on nobody can tell you much. chances are your friend used some weird code construct and it messed up the enginhe. Start by reinstalling AE and trashing the prefs entirely.
I've discovered this bug today on AE 17.7.0 and 16.1.3. It happens when I just try to click in the expression area without anything even in there, it's not tied to some weird expression. In 17 it will totally freeze and crash if I try to click in the text box area on the preferences screen he shows up there.
Attached is a screenshot of the window after clicking alt and position (AE creates the placeholder - transform.position) and the next image is what displays when you try to click into it, that white line is actually a massive cursor line. This is after I reset the preferences for AE v16.1.3, which another post suggested. I am running dual screens and tried this on both, but that doesn't seem to affect things at all. Also, both versions of AE claim they are the latest version. Hope someone can help, this bug makes working with expressions almost impossible. Thanks!