Hard drive issue.....no space?

Actually it’s an external hard drive. I’ve been trying to install some programs to it, which until recently, I was able to do. Lately though, some installers are saying there is no available space on it, even though File Explorer is showing I have over 182 Gigs free. I have no viruses, no malware, and other installers are picking up on the space available correctly, so what can I do to fix this issue?