Hey. Recently, the equalizer effect stopped working. Well, it does, but with serious mistakes. Always writing “Requested curve not found, using noname curve.” What should I do? I tried to set all versions of Audacity - the result is zero. I’m already tired of Audacity before the program didn’t pick on different details at all. But lately, it’s been beating my brains out… 
I’m guessing that you’re using an old version of Audacity?
Yes and no. I have this problem with new and old versions of Audacity.
The current version of Audacity is 2.4.1. It does not have an effect called “Equalization”, it has “Graphic EQ” and “Filter Curve EQ”.
Which version of Audacity do you have? (look in “Help > About Audacity”)
I’m using 2.2.2 version of Audacity right now. But I have this problem with other Audacity versions. For example in Audacity 2.3.0 on using Filter Curve through the Apply Chain… application says about the curve that not exist (but it exists and I even chose it in chains).
Try updating to Audacity 2.4.1. You can get it via the Audacity website: https://www.audacityteam.org/download/windows/
I didn’t understand how it happened at all, but after installing the newest version of Audacity all my problems went away. Thank you for your help.