The missing "Lens Blur" effect in After Effects isn't actually a bug, but rather an evolution of the software. Years ago, Adobe officially replaced the original plugin with the more powerful Camera Lens Blur .
: Search for "Missing" in the Project Panel to identify affected compositions. You must manually add the Camera Lens Blur effect and attempt to match the original settings as closely as possible. lens blur after effects missing free
Built-in Fast Box Blur + Scatter for soft focus The missing "Lens Blur" effect in After Effects
Some users attempt to "revive" the old effect by copying the Lens Blur.aex file from an older version of After Effects (like CC 2015 or earlier) into the Plug-ins folder of a newer version. Camera Lens Blur | Effects of After Effects You must manually add the Camera Lens Blur
A quick warning before you search YouTube for "Lens Blur After Effects missing free download." Many results will point you to cracked versions of Lenscare or Frischluft.