SOLVED: IntelliJ IDEA LESS compiler failure

I use IntelliJ IDEA for all of my web development work – it’s simply the best web IDE on the market, but I ran into a weird problem with the built-in LESS compiler recently. I cloned a project from the Github repo and set it up in IntelliJ. Everything was going well until I tried to compile the LESS files. I was getting weird errors whenever I tried to compile any LESS files in the project. Errors like this:

LESS CSS Compiler Error
mobile.less: Name Error: variable @screen-sm-max is undefined (line 2, column 20) near @media (max-width: @screen-sm-max) {

(This is weird because this variable is defined correctly)

or this:

LESS CSS Compiler Error
styles.less: org.mozilla.javascript.UniqueTag@15923b2d: NOT_FOUND Error: java.io.IOException: No such file file:/Users/admin/Desktop/_CLIENTS/Website%20build/BUILD/GIT/_WEB/styles/bootstrap/bootstrap.less (line -1, column -1)

(This is weird because it’s failing to compile Bootstrap, which I know is fine)

There was obviously something wrong with my setup because it worked fine for other developers. I was getting these errors when I used the “Compile to CSS” function or when I set up a LESS file watcher. I upgraded my LESS version. I spent a lot of time trying a lot of different things until I stumbled across this obscure thread.

That’s right. You can’t have any whitespace in the file path. My mistake was that the project was located in this folder:
Desktop/_CLIENTS/Website build/BUILD/GIT
Notice the space in “Website build.” I changed to folder name to “Website_build” and it worked. Note that manually adding “%20” into the file watcher path doesn’t work – you absolutely can NOT have any spaces in the path. I was kind of shocked at this problem. I thought we had gotten over this issue 20 years ago. Anyway, I’ve learned my lesson. No more folders with whitespace in the names. If this saves someone else a little time, then my wasted time will be worth something.