This can happen when you reinstall the operating system and want to add your games from hard disk (D, E etc.) to steam client.
1. Find your game folder. In this folder you can see "SteamApps" folder and file steam.dll. For example, "D:\Games".
2. Rename it. For example, "D:\Games2" (you can not add not empty folder to steam client as store).
3. Download, install steam client. Run it and log in.
4. Open "Menu - Steam - Settings - Downloads". Press button "Steam library folders".
5. Press button "Add library folder", Create and add "old" name folder, for example "D:\Games". Press "OK" button to save settings.
6. Restart steam client: "Menu - Steam - Quit" and start again.
7. Enjoy!
1. Find your game folder. In this folder you can see "SteamApps" folder and file steam.dll. For example, "D:\Games".
2. Rename it. For example, "D:\Games2" (you can not add not empty folder to steam client as store).
3. Download, install steam client. Run it and log in.
4. Open "Menu - Steam - Settings - Downloads". Press button "Steam library folders".
5. Press button "Add library folder", Create and add "old" name folder, for example "D:\Games". Press "OK" button to save settings.
6. Restart steam client: "Menu - Steam - Quit" and start again.
7. Enjoy!