Hi,
I’m installing the dblue crusher VST plugin into Audacity. However, when I click Allow in the add/remove plugins menu, it says “Unable to load library” or something similar. The path where I put the DLL file is C:\Program Files\Audacity\Plug-Ins
Am I doing something wrong here?
Audacity version: 3.1.3
"dblue crusher VST " is a 32-bit plugin: it will only work in 32-bit versions of Audacity.
Okay. How do I check if my Audacity is 64-bit or 32-bit?
By default you will be served-up the 64-bit version of Audacity 3.x.x
If you want the the 32-bit version you have to seek it out:
it’s on this page … Audacity ® | Download for Windows
[ 32-bit version will not run 64-bit plugins, and vice versa]
I found a 32-bit installer on that page, and also a .zip file. Do you think the 32-bit installer would work on a 64-bit machine?
Yes it will, but I use the zip version to keep it completely separate from the 64-bit version.
Unzip it into a folder, then launch it by double-clicking on the “Audacity.exe” icon in the folder.
Okay, I’m downloading the .zip.
It worked!
Glad you got it sorted. 
FYI. While running Audacity, select Help > Audacity > Build Information.
The 3rd line under “The Build” will say “32 bits” or “64 bits”.