F# Interactive Unresponsive/Freezes/Hangs

Over the last few weeks, on Visual Studio 2017 (15.9.9-11), Visual Studio 2019, VS Code, PowerShell, and CMD, I have encountered a weird issue. When I code directly into the F# Interactive windows, F# Interactive just freezes: It is OK when I send a piece of code to it from a script (ALT+ENTER) but not when I do it directly. Interestingly, when I enter code directly into FSI, nothing happens, but as soon as I send something from a script, it evaluates whatever code I previously entered in FSI as well. You could see the blinking cursor going on forever under “> 2+2” - I tried it for 2 days and nights just for the heck of it.

Try adding ;; (2 semicolons) at the end of your command


Well sort of weird, but I had to add ;; to anything beyond 1-liners in scripts as well and everything was ssslllloooooowwwwwwwwwwwwwwww. Ended up doing a clean install and voila, so far so good.