Fixing Steam 0 bytes available disk space issue when removing a drive from the system

 Ran into an issue this weekend, so I'm memorializing it here. 

I had two drives in my system, one SSD for the OS and one high capacity spinning drive for secondary, slower storage. The second drive is where I put my Steam Library.

I pulled the drive this weekend to put into another machine I'm using for temporary file storage while I migrate Synology servers (longer story). This 1TB drive was holding my Steam Library.

I went into Steam, and Steam recognized that the SteamLibrary folder was no longer present and set the default back to the C:\ drive. I thought I was all good.

Fast forward a week and I have picked up a used NVidia card, and wanted to test it out. Went to download/reinstall the game and Steam says there's "0 bytes available" even though there's no other Steam folder, and the DEFAULT is set to the C:\ drive.

Here's what I did, that wasn't covered by other posts and threads I found: 

1) Go to Steam Settings

2) then Downloads

3) then click Steam Library Folders

4) then right-click on the directory shown and click on Make Default Folder. (yes, yes, even though it says it's already the default)

5) then right-click on the directory again and click on Repair Library Folder. Steam will restart.

You're done. Try installing games again.